Introduction and overview

DAVID CHRISTIAN

As Merry Wiesner-Hanks writes in her series preface, the Cambridge World History is authoritative and comprehensive, but not exhaustive. World his­tory must limit its ambitions precisely because its scope is so vast, so an exhaustive history of humanity, like a map the same size as the landscape it charts, would be of little use because it would have avoided the hard work of distillation.

Volume I is introductory in two distinct senses. Part I is about world history as a sub-discipline of history, while Part II is about the earliest phases of world history.

Part i introduces approaches, methods, and themes that have shaped and defined scholarship in world history. It ranges over world history as a whole, but does not visit every village and province. For readers new to the field, these chapters can illustrate the diversity of approaches that historians have brought to the project of world history. For world historians, they will offer recapitu­lations of important themes and approaches, and introductions to some less familiar aspects of world history. Many of the themes and topics introduced here are taken up with greater chronological and geographic specificity in the chapters in the second part, and also in later volumes in the series.

I have received a lot of help in editing this volume. First, I would like to thank Merry Wiesner-Hanks, who played a huge role in putting this volume together, as she did with all the volumes in this series. Second, I would like to thank Marnie Hughes-Warrington, who worked with me as we planned the basic structure of this volume.

Part ii surveys the earliest phases of human history during the Paleolithic era: the vast period extending back hundreds of thousands of years, in which our human and hominin ancestors laid the foundations for human history. As is appropriate in a volume intended mainly for those interested in the human past, it concentrates on the most recent phases of hominin evolution, the rise of our own strange species, Homo sapiens, and the very earliest human societies. Part ii closes at the end of the last ice age, just over 10,000 years ago, when in some parts of the world some of our ancestors took up agriculture. Agriculture allowed human communities to divert more and more of the biosphere's energy income to their own support, and is explored in depth in Volume 2 of this series, A World with Agriculture. The resulting energy bonanza would drive human history into utterly new pathways, transforming human communities and accelerating the pace of change throughout the world, developments examined in Volumes 3 through 7 of this series.

This Introduction summarizes the chapters in the two parts of Volume I. It describes some of the main themes of each chapter and makes comparisons among them, but inevitably skips most of the evidential detail and interpret­ative nuance. Like world history itself, it is a distillation, in this case a distillation of distillations, but some readers may want to use it as an extended table of contents before going on to the chapters themselves.

Part i : Historiography, methods, and themes

As a sub-discipline of the modern history discipline, world history is surpris­ingly new. In the words of the late Jerry Bentley: ‘As it has developed since the 1960s and particularly since the 1980s, the new world history has focused attention on comparisons, connections, networks, and systems rather than the experiences of individual communities or discrete societies'.¹ Most modern world historians have been trained as historians, so they accept the discipline's ground rules.

The impulse to a more global understanding of the past has been driven in part by globalization and decolonization. Shifts in the global balance of economic, military, and even intellectual power and increasing global con­nections between scholars have exposed the severe conceptual and empirical limitations of the nationalistic and Eurocentric attitudes to the past that dominated historical scholarship in earlier centuries. The same pressures have encouraged more and more historians to explore the past as part of a shared human heritage. Paradoxically, that move has also taught us that world history is not as new as it may seem at first sight. Indeed, some form of world history can be found in most human cultures.

As Marnie Hughes-Warrington points out in her brief history of world history in Chapter 2, we find many different labels for the same core project. They include ‘universal history', ‘global history', ‘transnational history', ‘macrohistory', ‘comparative history', ‘big history', and more. She also points out that, whatever we call it, the world history project is ancient. All attempts to make sense of the past depend on imagining a coherent and meaningful ‘world' of some kind, though they vary in the extent to which ‘the purpose of world construction is explicit'. But as this suggests, constructing a world that is ours also encourages an interest in the worlds of others. Over 2,000 years ago, Herodotus in Greece and Sima Qian in Han China drew sharp lines between their own world of civilization and the barbarous realms beyond the borders.

Printing, the ‘philosophical turn' of the Enlightenment, and the profes­sionalization of scholarship in the nineteenth century might have helped erase these lines, but in practice, they redrew them. Historians became entranced by the nation state and the challenge of constructing national histories; and world history fell into disfavour. Much world history continued to be written, often outside the formal structures of the history profession, but from the late nineteenth century, professional historians began to frown on the practice. From the middle of the twentieth century, new themes for historical research, including modernization, world-systems, area studies, and post-colonial studies encouraged new ways of framing historical problems.

So, too, did new approaches to history in general, including gender history (Chapter 10), environmental history, and the rapid increase in research on inherently worldish themes such as migration (Chapter 12). This broadening of the scope of historical research, along with increasing global integration, helps explain the modern revival of world history within the institutional structures and conventions of modern historical scholarship.

Dominic Sachscnmaicr's Chapter 3 also surveys the history of world history. But while Hughes-Warrington notes the importance of world history scholarship outside the academy, Sachsenmaier focuses on secular academic writing in world history. He agrees that in some sense all history is world history, because every community and every historian understands the past as the past of a particular ‘world’.

In any culture and time period, the history of the world could only possibly mean the history of one’s own world, that is, the world one was exposed to through lived experiences, personal travels and the accounts of others.

Of course, such world histories always had to take notice of ‘others’, so that Sachsenmaier, like Hughes-Warrington, notes a fault line in all early world histories (and perhaps within the very nature of world history) between our world and the world of others, a tension visible at least from the time of Herodotus and Sima Qian and apparent also in Muslim historiography. Indeed, the very idea of world history seems to imply an interest in what lies beyond ‘our’ world.

From the sixteenth century, the number of possible ‘other worlds’ multi­plied. Connections with worlds never imagined before helped detach world histories from their traditional roots, particularly in Europe. The creation of the first global networks of exchange prompted the earliest attempts to write history on planetary scales, such as George Sale’s 65-volume Universal History, published between 1747 and 1768. But globalization also sharpened the familiar dichotomies of world histories, now re-cast as contrasts between Europe and the rest of the world. European writers as influential as G. W. F. Hegel, Karl Marx, and Max Weber put Europe at the centre of their global vision, and pushed other regions to the margins: ‘Generally speaking, the rest of the world was seen as too far behind the Western engine to be seriously studied as a guide or reference’. Eurocentric world histories became less Universal and less ‘worldish’.

Globalization also shaped historiographical traditions outside of Europe, but in different ways. Outside the emerging ‘West', national historiograph­ical traditions emerged in tension with or opposition to the history of the West, which was often re-classified as ‘world history'. Here, therefore, ‘world history' gained in importance because it meant the study of ‘the West'.

In the twentieth century, several historians tried to break with overly Eurocentric approaches to the past. They include Oswald Spengler, who offered a vision of a declining West; Arnold Toynbee, who described a world of multiple distinct ‘civilizations'; William McNeill, who stressed the import­ance of connections between civilizations; and other historiographical trad­itions such as world-systems historiography and the Negritude Movement. But their impact on historiography was limited until after the collapse of Communism in the last decade of the twentieth century. The breakdown of Cold War divisions gave a powerful new impetus to research on global processes and global connections, which is why world history can seem like a new historiographical project. But even today, and even in work produced by world historians, there remains a complex but powerful tension between traditional ways of framing the past around regions or nations (traditions still supported by the educational policies of most governments), and attempts at more global accounts of the past, ‘bordercrossing scholarship', as Sachsen- maier calls it. We should not expect a homogeneous global historical scholarship to emerge from these efforts, but what we can expect is increas­ing dialogue between different traditions of world history scholarship.

In Chapter 4, Michael Lang tackles the problem of periodization. Though fundamental to all historical writing, periodization takes distinctive forms and raises distinctive problems within world history. ‘To use the language of Kracauer and Adorno, the historiographical period is a “force field.” It is pulled between poles of chronology and immanence, perpetually in tension, and without resolution'. By its very nature, the idea of a period hints at ‘the universal of time, and therefore indicates, even when unexpressed, the history of the world'. Lang describes a series of attempts within modern historiography to manage the tension between the particular, and what Leopold von Ranke called the ‘great whole' of universal history.

When Ranke wrote, periodizations based on national histories were already shaping much historical scholarship. But most historians retained a sense of multiple times, from those of evolution or geology (‘nature's epochs' in Comte de Buffon's phrase), to the ‘innumerable times, all at one time' of Johann Gottfried Herder. Ranke saw the nation itself as a partial resolution of the tensions between universality and particularity. The state itself was a sort of universal, integrating many within a larger unity; but of course each state was also its own specific universal. At times, though, even Ranke found the tensions insoluble, at least for humans: ‘God alone knows world history. We perceive the contradictions'.

Other nineteenth-century historians were equally sceptical of universals, and equally captivated by the strange universal of the nation state. William Stubbs wrote that history showed endless differentiation rather than ‘elemen­tal unity'; yet he wrote, too, of a larger English national identity. At a more practical level, of course, the state provided a sort of methodological universal in the nineteenth century because it shaped not just the thinking of historians, but also the institutions they worked in and the conventions that shaped their careers and scholarship. And, as if to illustrate the tensions that frustrated Ranke, each state shaped historical scholarship in its own distinctive way.

In the twentieth century, the national conflicts that helped generate two World Wars undermined the assumption that the nation state offered a natural frame for historical periodization. But what could replace it? Toynbee offered civilizations. McNeill offered the world as a whole and the history of humanity as an evolutionary process. Was there a ‘meaningful past' shared by humanity as a whole? McNeill found periodizations for such a past in processes of cultural diffusion (or even epidemiological diffusion) that linked large areas through evolutionary patterns of change. McNeill was not alone in seeking new universals. But is there a danger that, as Lang puts it, world history merely ‘shifts the spiritual unity of the nation onto the world as a whole'? Many modern historians and historiographers have been deeply suspicious of such apparently universalizing projects. Martin Heidegger, Michel Foucault, and Jacques Derrida insisted on the selectiveness of univer- salist histories and the roles they played as ideologies and as forms of power. But what was the alternative? Was it perhaps to move back towards the specific and the contingent, towards the world of lived experience? In 1956, Roland Barthes wrote: ‘It seems that this is a difficulty of our epoch... either posit a reality which is entirely permeable by history and ideologize; or else, inversely, posit a reality ultimately impenetrable, irreducible, and in this case, poeticize'. So, while attempts at world history moved towards universality, postmodern or post-colonial history moved towards particularity. ‘Between these poles - chronology and immanence, evolution and rupture, universal­ity and meaning - historiography employs the period'.

While Lang's chapter sees no easy resolution to the problem of periodiza­tion in world history, in Chapter 5 David Northrup defends a powerful but extraordinarily simple periodization of human history. For most of human history we see divergence and diversification. But then, during the last thousand years, we begin to see convergence everywhere. ‘At some point, centrifugal forces for global divergence began to be overtaken by centripetal forces for convergence. Despite some interruptions, that trend continued and gradually gained momentum. This was the Great Convergence'.

As Northrup points out, the most influential historical periodizations have cut across the very project of world history. Some, such as the traditional European partitioning of the past into Ancient, Medieval, and Modern periods, work best for particular regions; while some periodizations ignore everything before Sumer; and others ban the historical study of today's world. Yet world history cannot ignore the problem of periodization without turning into a random collection of local histories. The simple periodization Northrup proposes really is global; it embraces the whole of human history; and it encourages discussion of future trajectories.

For most of human history long-distance exchanges were limited, and each community constructed its own distinctive history. Genomes diverged, so did languages, lifeways, and religious beliefs and rituals. Early modern Papua New Guinea illustrates the spectacular possibilities for linguistic divergence. Here, ι million people spoke 500 distinct languages from 33 different lan­guage families. Similarly, a single proto-Bantu language split into 250 different languages in less than 3,000 years. In retrospect, historians can see the commonality between these languages; contemporaries were surely more aware of the differences.

Today, though, the commonalities are more apparent. English and Span­ish have spread not as language families, but as single languages, while many local languages are dying out so that the total number of languages is declining fast. Meanwhile, diseases, technologies, and conflicts (or news of conflicts) hurtle around the globe, creating what V. S. Naipaul called ‘universal civilization'. When did convergence become the dominant trend? Regular contacts between all parts of the world began only in the sixteenth century, but Northrup argues that convergence has deeper roots. We find important exchanges of people, goods, ideas, and ritual objects deep in the Paleolithic. In the last 5,000 years, empires and trading diasporas multiplied exchanges of goods, ideas, fashions, and religions. When did the balance tip? Northrup inspects several possible dates before opting for 1,000 ce, when, as John Man argued, one can for the first time imagine a message being transmitted right around the inhabited world. Perhaps, as Northrup argues, the problem of periodization in world history is not quite as intractable as some historians imagine.

In Chapter 6, Luke Clossey explores the world history of ideas and thought. Can there be a world history of belief, knowledge, and language? This chapter, too, is shaped by the problem of Eurocentrism. It tracks the evolution of the idea that European science and secularism have colonized the world of thought, and it asks if a world history of ideas should or can yield a more ecumenical history of human thought.

In fact, as Clossey points out, there has been little ‘world history' of ideas. ‘Most of our books about knowledge are in fact about Euro-knowledge, rather than about the Wider World's ethno-knowledges'. Even the idea of ‘ethno-knowledges' implicitly distinguishes them from ‘knowledge' pure and simple, which is assumed to work everywhere, while ethno-knowledges are assumed to work only on their home grounds. Can we (particularly if ‘we' are historians based in the ‘West') possibly study ideas or beliefs free of such assumptions?

Some of the earliest attempts at a worldish understanding of religion and language were European, the products of some of the earliest global empires. But they launched a tradition of comparative scholarship that, in retrospect, seems surprisingly un-Eurocentric. That tradition begins with the work of William Jones, an English judge in British Bengal who lived in the eighteenth century and initiated the comparative study of languages and religions. The tradition he began was continued in the work of the philologist, Max Muller, and in that of George Sarton, who founded a journal on the history of science, called Isis, in 1927. Sarton came to appreciate the crucial role of Muslim science and duly learnt Arabic to pursue this insight.

Eventually, though, historians of thought became dissatisfied with the broad generalizations of the pioneers, and began to narrow the scope of their work, focusing increasingly on regional traditions, which they often portrayed as foils to modern European science. Seeing European thought itself as a local tradition is not easy, though there have been some remarkable attempts, such as Eric Wolf s Europe and the People Without History, and Dipesh Chakrabarty's Provincializing Europe. But even these help us do little more than nibble at the edges of Eurocentrism in the world history of thought.

The rest of Clossey's chapter assesses the nature and extent of Eurocen­trism in debates over four worldish topics: hominization (the processes by which our ancestors became human), the idea of the Axial Age, the study of the European Scientific Revolution, and the idea that religion is in decline in the modern world. In all four discussions, he finds that Eurocentrism survives in subtle and not-so-subtle forms, despite growing awareness of its limitations. For example, it might seem that the study of hominization has to be ‘worldish'; yet even here it is possible to identify subtle forms of Eurocentrism, if only because so many of those who study the subject are European or Western. (Some of the consequences will be discussed in Chapter 16.)

And this may lead to the heart of the problem of Eurocentrism; so much world history is the work of ‘Western' scholars. So it is hardly surprising if a casual survey of courses and textbooks used in the University of Cambridge yields a list of ‘knowledge makers' that is overwhelmingly European. Simi­larly, a quick survey of modern world history textbooks shows that science looms large in accounts of Western societies, while religion looms larger in accounts of non-Western societies. Is it surprising if a world history domin­ated by Western scholars is Eurocentric? And even if we can imagine a non- Eurocentric world history of thought, will it simply be from the perspective of another ‘centrism', like the delightful Beijing History of the World, published in the year 2174, with which Clossey ends his chapter?

In Chapter 7, Dan Headrick explores a specific but critical aspect of intellectual history: the history of technology and innovation. Headrick defines technology as: ‘the use of materials, energy, and living beings for practical purposes'. Of course, we can identify technologies in many non­human species. But humans are so good at dreaming up new technologies, and technological innovation has given our species such power over our surroundings (and over each other), that technological innovation counts as a defining feature of humanity, and a fundamental driver of human history. Despite this, the history of technology is a relatively new field of historical research; it is hard to trace it back much further than the Enlightenment and the Encyclopedie (1751-72). The first serious scholarly treatment of the history of technology is Johann Heinrich Moritz von Poppe's Geschichte aller Erfin- dungen und Entdeckungen im Bereiche der Gewerbe, Kunste und Wissenschaften von der Jruhesten Zeit bis auf unsere Tage (History of all the Inventions and Discoveries in the Trades, Arts, and Sciences from Earliest Times to Our Day), first published in 1837. In the decades that followed, many scholars and thinkers, including Marx, took up the idea that technological innovation

might be a fundamental driver of historical change. As Marx famously wrote in 1847, in his critique of Pierre-Joseph Proudhon, The Poverty of Philosophy: ‘The windmill gives you society with the feudal lord; the steam-mill, society with the industrial capitalist'. Such claims raised a fundamental question for historians: if technological innovation is a powerful driver, what drives technological innovation?

Rapid technological change stimulated popular interest in technology in the nineteenth century. That interest was evident in the great exhibitions, beginning with the French industrial exposition of 1844; in the building of museums of science and technology, and museums dedicated to particular technologies, such as the railways; as well as in exhibitions such as Sturbridge Village in Massachusetts, which recreated displays of traditional technologies such as blacksmithing. Scientific American, a journal dedicated to dissemin­ating information about science and technology, was founded in 1845. Popu­lar interest in technology was normally, as Headrick puts it, Whiggish'. It assumed that technological and scientific change represented progress; and it assumed technological determinism - the belief that technological innov­ation drove historical change. Like many other historical sub-disciplines, the history of technology also fell into the force field of nationalistic historiography, as historians defended national claims for technological leadership. Was it a Briton, William Fox Talbot, who invented photography, or a Frenchman, Louis Daguerre? Was it a Frenchman, Clement Ader, who pioneered heavier-than-air flight, or the American brothers, Orville and Wilbur Wright?

Modern scholarship in the history of technology really begins in the twentieth century. George Sarton's multi-volume history of science was exceptionally broad in its approach and particularly in its willingness to highlight the achievements of Islamic science. Classic studies, such as those of Lewis Mumford and Abbott Payson Usher, also approached the history of technology with unusual sophistication. But much scholarship remained nationalistic and individualistic, focusing largely on the work of individual inventors.

The history of technology matured as a field after the Second World War, with the emergence of new journals and scholarly societies (such as the Society for the History of Technology, SHOT). The field became less Whiggish, more interested in technological failures, and less interested in the national origins of particular technologies. The International Committee for the History of Technology, founded in 1968, encouraged a more global approach; while scholarship by Joseph Needham and Vaclav Smil helped undermine the field's Eurocentric traditions. Needham's work, possibly the most important scholarship in the field in the twentieth century, raised the possibility that China was the world's technological leader until the fifteenth century. Global studies of particular technologies, such as firearms, demon­strated the extent to which innovation depended on (or in some cases was limited by) cultural diffusion. The work of Leslie White helped encourage interest in ancient technologies and the archaeology and anthropology of technology. Social historians and gender historians began to explore the social contexts and social consequences of innovation; Ruth Schwartz showed, for example, how labour-saving technologies could increase the burden of domestic labour.

As the field becomes both more mature and more global, we see increas­ing research into the social roots of innovation within international networks of commercial and informational exchange. Are we at last approaching a genuinely worldish history of technology, an update, perhaps, of von Poppe or Sarton for the twenty-first century?

In Chapter 8, Johan Goudsblom explores a particular cluster of technolo­gies: those associated with fire. All human societies control fire, but no other species does. So fire management counts as a ‘species monopoly', a defining feature of our species and our history. The ability to manage fire is also a clear product of cultural accumulation or ‘collective learning'. So, we can say that the human relationship to fire is ‘unique, universal, and cultural'. Though the early history of fire management remains unclear, there is a case for counting it as the first technological threshold in human history.

Fire is a form of energy and, like all forms of energy it can be used to manipulate matter. But to manage fire you need information, so to under­stand how humans have managed fire, we need the conceptual triad of energy, matter, and information. Fires need oxygen, so they must have been rare and short-lived before the appearance of an oxygen-rich atmosphere 2-3 billion years ago. They also require fuel, which probably means they were rare before the spread of plants on land in the last 400 million years. Finally, fires need temperatures high enough for ignition, but these can be supplied by many natural forces including lightning. So our hominin ancestors must surely have been familiar with fire, like all living organisms today.

There must have been a long period of increasing familiarity with fire, which is discussed in recent work by Frances Burton. Then, at some point in the last 2 million years, our ancestors became the first species capable of managing fire, creating it at will, and harnessing it to their own purposes, using accumulating cultural information to do so. The earliest firm dates for controlled use of fire by hominins date from 250,000 years ago, though some archaeologists have argued that there is good evidence of fire management from Israel and South Africa as early as 800,000 years ago.

As the great sociologist Norbert Elias would have insisted, controlling fire also surely meant increasing control by humans over their own behaviour. One of these behaviours may have been cooking. Richard Wrangham has argued that fire was critical in human evolution because it allowed our ancestors to cook (in other words to ‘pre-digest') high-value foods such as meat, or foods that were toxic or could not be digested raw. The technology of cooking represented an energy revolution for our ancestors, as it provided high-energy foods in easily digestible forms that used little metabolic energy. A shortening of the human gut within the last 2 million years may be an indirect sign of the importance of cooking and therefore of fire management. Fire also offered an important defensive weapon, as well as a focus for increasing sociability. In the form of what is known in Australia as ‘fire-stick farming', fire also provided a foretaste of agricultural intensification, as it was used to increase the productivity of the land.

Fire played a vital role in the second great technological revolution of human history: agrarianization. Farmers increased the production of favoured species of plants and animals by re-arranging the environments they inhabited. By doing so, they increased the resources and energy avail­able to human beings. Fire was used to clear land (in slash and burn farming), so it was responsible for much of the deforestation of the Neolithic era. New and more specialized uses of fire also encouraged an emerging division of labour in occupations from blacksmithing to soldiering. On the other hand, fire brought new forms of danger, especially in towns and cities, whose closely clustered houses and workshops, each with its own fireplaces, pro­vided the fuel and ignition for many a conflagration. Fire was both necessary and terrible. Not surprisingly, it looms large in myths and religions, as a god­like force, or as a power to be seized and used, as in the Prometheus legend.

Fire technologies also drove the third great technological revolution, that of industrialization, which depended on vast new supplies of fuel from coal, oil, and natural gas. Unlike traditional fuels such as wood, which released energy accumulated over just a few decades of photosynthesis, fossil fuels stored energy accumulated over hundreds of millions of years. The ‘subter­ranean forest' of fossil fuels (as Rolf Peter Sieferle described it) drove new and vastly more powerful technologies of manufacturing and transportation. Concentrated forms of fire also became important as weapons of war; even most victims of nuclear weapons died from fire. Eventually, electrification allowed the indirect consumption of the energy of fire because the fires that supply electricity do their work far from the point of consumption. That may be why, today, it is so easy to ignore the role of fire in our lives. And that, in turn, may explain why today we talk of ‘energy' rather than using the more vivid, even animistic images of fire present in most earlier societies. But fire itself is still omnipresent, both as a source of energy and as a source of danger, even if it prefers to work behind the scenes. Eventually, though, if we keep using the energy of fire on today's scales, we may have to acquire it in new forms, perhaps by finding new ways of tapping its energy directly from the largest source of fire in our solar system, the sun.

From technologies to social institutions. Chapter 9, by Mary Jo Maynes and Ann Waltner, discusses the family and household as central themes within world history. They suggest using the concepts of ‘domestication' and ‘biopolitics' to link family history and global history. Many archaeologists have used the term, ‘domestication', to refer not just to the Neolithic era domestication of plants and animals, but also to the self-domestication of humans, and the emergence of new forms of family with ‘the cultural invention of human domestic life'. Indeed, the Neolithic family and house­hold were vital to human self-domestication. Clive Gamble argues that the earliest Neolithic communities may have been the first ‘to develop fully modern minds and a fully symbolic culture'. Such approaches point to a powerful dialectic between the family and the state. They have encouraged research into families as objects of legislation and control, as key structures in the exercise of both political and commercial power, and as managers of labour and consumption. The notion of ‘biopolitics' stresses the importance of political control over human bodies including attempts to count and measure them, and to regulate fertility and family structures. Michel Foucault famously described spectacular examples of biopolitical regulation in the modern world, but biopolitics, like domestication, can be traced back at least to the early Neolithic.

Of course, family relations of some kind pre-date the Neolithic both in the real world and in the world of scholarship. Until the 1970s, the widely accepted notion of ‘Man the Hunter' implied a Paleolithic world of acquisi­tion and production driven by the activities of males and a reproductive world of females shaped by biology rather than by culture. Feminist revisions of these models, and new interpretations of the scattered archaeological evidence, have highlighted the central role of females in production, the constructed nature even of Paleolithic families and their reproductive behav­iour, and the importance of households in demographic behaviour, and in the education and socialization of children.

Given the importance of women as gatherers in many foraging societies, it is likely that women played a significant role in the transition to agriculture. Indeed, genetic evidence suggests that marriages between communities of farmers and foragers may have helped spread agricultural technologies and lifeways. Clive Gamble has argued that the Neolithic Revolution transformed patterns of child rearing and socialization, creating entirely new ‘childscapes’, new environments that transformed childhood experiences. Ian Hodder argues that the family and household were critical agents of socialization. For example, environments such as the cheek-by-jowl residences of the famous Turkish site of Qatalhoyuk created childscapes that taught children how society and social networks were organized: ‘important elements of social organization - cooperative production following a division of labor, settlement building, and kinship rules - all emerged without any form of the state. Social complexity here too focused on the local and the household’. The household could teach even deeper rules. In Qatalhoyuk, internal burials connected the past to the future through distinct generations, creating a powerful sense of the movement of time. Such structures even carried cosmological information. For example, Egyptian cosmologies tell of gods linked by family ties, within which each god had its own distinctive role within a larger family network. Thus, in one telling, ‘Isis discovered seeds and Osiris taught the Egyptian people how to plant them’. The monotheistic religions, on the other hand, offered cosmologies that implied clear gender hierarchies, and it is tempting to associate them with the emergence of new forms of patriarchy. However, religious cosmologies could also seem at odds with family structures, for example when they idealized celibacy, as Buddhism did in some forms.

Families provided idealized templates for states and political structures. Male rulers often represented themselves as members of ancient descent lineages through the male line, while Chinese philosophers described a well- ordered state on the analogy of a well-ordered family. The metaphors cut both ways: ‘likening the power of the king to that of the father naturalized both masculine political power and masculine authority in the household’. The result was a sort of naturalization of political power, making its rules and authority seem as self-evident as those of the family. And that, perhaps, explains why from the very earliest states, rulers tried to regulate family structures. Fully a third of Hammurabi’s law code of the eighteenth century BCE was concerned with the family. Less metaphorically, family structures often provided the sinews of political power and determined political rights such as citizenship.

Precisely because family structures seemed so self-evident, those who encountered new rules about marriage, kinship, and sexuality often found them peculiarly shocking. Such encounters multiplied from the sixteenth century. In Southeast Asia, traders from Europe and China were horrified by marriage practices that simplified divorce and allowed women to engage actively and publicly in commerce. Such reactions help explain why colo­nial rulers, such as those of New Spain, worked so hard to impose their own ideas and laws about how families should function. On the other hand, slave owners made and re-made the family structures of their slaves according to commercial calculations. In these ways, early forms of global­ization began to transform kinship structures and ideas in many parts of the world.

As families changed so, too, did the metaphors they provided for the organization of social and political life. Lynn Hunt showed how, during the French Revolution, the idea of fraternity challenged older metaphors of paternal authority. As modern states extended their administrative reach, they began to measure and regulate domestic life in greater detail and with greater success than ever before, until in the twentieth century, biopolitics, ‘the routine state surveillance, measurement, and management of human life', became a normal function of governments throughout the world. The most brutal forms of family regulation were associated with colonial regimes, or with the family and racial politics of fascism and the ideas of eugenics. But in more modest forms, the rules of family life - who can marry whom, what the ideal family should look like, and how big it should be - have become routine objects for government regulation, bringing the two domains of government and the family, and the two historiographies of politics and the family, ‘ever closer together'. Families, it seems, have structured the worlds of every human, in every part of the world; but they have also structured many aspects of social and political life at larger scales.

In Chapter 10, Merry Wiesner-Hanks takes up the ‘oldest category of difference in human history', that of gender. Gender, like the family, has structured human lives at such a deep level that it must loom large in any serious world history.

The category of gender looms large in recent historiography, along with other categories of difference and identity, as the nation has lost its centrality in historical thinking and research. World history, too, represents an attempt to find new ways of framing our understanding of the past, but, curiously, world history and gender history moved for several decades along parallel paths before eventually intersecting.

Most human communities have assumed the existence of dual gender roles. These roles have often been projected symbolically onto the world and the cosmos, as male and female principles, as yin and yang, as private and public. Gender dichotomies have shaped not just the roles of individual men and women, but also how men and women have understood their roles within the family and society. So intimate and pervasive are gender dichotomies that, like the kinship networks in which they are embedded, they have usually been experienced as natural, as intrinsic to the way the world is. This is despite the fact that, biologically speaking, gender is more complex than conventional dualities imply. Indeed, some societies do find room for third or in-between genders. Modern scholarship on gender is sensitive to these complexities, and careful to distinguish between cultural and biological aspects of gender. This means that: ‘gender is generally understood to be a culturally constructed system of differences based on physical, morphological, and anatomical differences between the sexes, what are often called “biological differences'”.

Gender differences imply more than difference. In all societies that have left records, gender dualities have been interpreted as hierarchies, with the male side being interpreted as stronger or more positive. So, as Joan Scott put it in 1986: ‘Gender is a constitutive element of social relationships based on perceived differences between the sexes, and gender is a primary way of signifying relationships of power.'

Traditionally, assumptions about gender seemed so fundamental that most historians overlooked them. Most historians were male, they took existing gender roles for granted, and they saw the past through male eyes and male preoccupations. Only since the rise of a women's movement in the nineteenth century have historians begun to see gender roles more clearly and to take them more seriously. And not until the second wave feminism of the mid twentieth century did feminist historians begin to show the extent to which ‘history' was in fact ‘male history', or history through male eyes. But attempts to write a distinctive ‘women's history' often fell into the trap of writing it within pre-existing categories, such as those of class or nation. By the 1980s, increasing numbers of historians particularly in the English­speaking world began to study both male and female history through the category of gender, because it raised deep questions about how the roles of both women and men have been constructed and negotiated over time.

Partly under the pressure of gay rights movements, beginning in the English-speaking world, traditional gender categories began to be questioned at even deeper levels, generating renewed interest in the history of sexuality in general. Just as women's history had begun to explore men’s history and then gender history, so, too, the history of homosexuality turned to the study of heterosexuality, and then to sexuality in general, and, particularly within ‘queer theory’, to forms of sexuality that did not fit comfortably within established or dominant dichotomies. Such studies showed how gender and sexual categories normalized and ab-normalized specific roles and behav­iours. A particularly important theme in the emerging historiography of sexuality was the question of whether there were distinctively modern attitudes to gender and sexuality, or whether, perhaps, the categories them­selves were products of modernity. Were these categories constructed by some of the same pressures and processes that lay behind modernity more generally?

Increasing interest in how historians constructed the categories they used to understand the past may help explain why historians of gender and sexuality were attracted to the broader historiographical movement often known as ‘the cultural turn’. This fundamental shift in perspective moved historians from study of evidence about the past as it ‘actually happened’, in the words of Ranke, to study of how historians used evidence to construct accounts of the past. That move encouraged the idea that historians can never really study an unmediated past; at best, they can study the images historians and others have constructed of the past. Michel Foucault showed the extent to which those images, and even the language in which they were described, supported and reproduced existing power relations. His insight lent a critical edge to the study of historical dis­courses, including those of gender and sexuality. It also suggested the extent to which domination depended on collusion from below, an idea developed in Gramsci’s notion of ‘hegemony’, another concept that proved attractive to historians of gender and sexuality. Extreme forms of ‘social constructivism’ ran the risk of depriving historians of any intellectual leverage, because they lacked anchors in a real world. But in more modest forms, the cultural turn sensitized historians in many different fields, including gender history, to the cultural filters through which historians view, describe, and explain the past, and to the many ways in which those filters also shape the present.

Eventually, the parallel tracks of gender history and world history began to overlap. Like gender history, world history attempted to break from established historiographical categories such as the nation state. But different historiographical breakouts led in different directions. While gender history worked with differences, world history looked for connections; and while gender history veered towards cultural history, world history usually stayed closer to the materialist traditions of earlier historical scholarship.

There are, nevertheless, many natural points of contact between gender history and world history, and they will be emphasized at many points in various volumes of the Cambridge World History. They include studies of early human societies, of marriage across cultural lines, of the construction of national identity, of migration, and of colonialism. Interest in the earliest eras of human history has encouraged both world historians and gender histor­ians to re-interpret social and gender relations in Paleolithic societies. Modern accounts of Paleolithic societies emphasize the role of women as much as (and sometimes more than) the role of males (see Chapter 9). Gender and world historians have also found common ground in studies of how gender has shaped national identities and symbols. Was homosexuality compatible with full citizenship even in relatively liberal societies such as the USA? ‘Often not' is the answer of historians such as Margot Canaday and Jasbir Puar. Gender roles also shaped migration, but the intersection of gender relations and global power relations has been particularly striking in studies of colonialism, where strongly held notions of gender and the family shaped many of the cultural and legal structures of domination.

Both world history and gender history have been forced to question and destabilize established dichotomies of domination and of gender. Research linking these once distinct historiographical traditions has added depth to both fields. It has shown the extent to which world history is itself gendered in content and construction, as well as the global reach of the themes explored by gender history.

In Chapter ιι, Jack Goody describes the long, complex, and fraught relationship between world history and anthropology: another discipline that has attempted to understand humanity at large scales and has wrestled long and hard with Eurocentrism.

Goody has played an active role in the complex relationship between these two disciplines, and he argues that they have much to offer each other. Both world history and anthropology (and the closely related discipline of compara­tive sociology) aspired to an ecumenical understanding of humanity. But while history favoured written sources, anthropology preferred oral sources. For much of the twentieth century, these methodological differences drove the two fields apart. This was particularly true after the work of Bronislaw Mal­inowski and his followers encouraged anthropologists to engage in detailed field work in non-literate societies, and to focus on the distinctiveness and specificity of each culture. The broader theoretical perspectives of earlier anthropologists, such as Edward Tylor or James Frazer or Emile Durkheim were increasingly taken up within a different field, that of comparative sociology.

One odd consequence of this division of labour was that many anthropolo­gists continued to study even complex societies such as India and China using the methods and assumptions they applied to small-scale societies. Often, that meant ignoring written sources. The result was to preserve nineteenth­century distinctions between a modern West and an archaic East. However, such approaches were undermined in the twentieth century by the work of Joseph Needham on Chinese science. As Goody writes: ‘I myself was much struck by the fact that until the Italian Renaissance, as Needham claimed, science was more advanced in the east than in the west'. China's economic weight, too, was long underestimated within a Eurocentric world history despite the discovery that it was: ‘the greatest exporter of manufactured products until the end of the eighteenth century'.

Though they have long travelled on different trajectories, anthropology and world history have much to offer each other. Anthropology has helped world history find new types of sources, beyond the books and records, and also to become less Eurocentric and avoid some traditional assumptions about Western exceptionalism. For example, anthropology can show that democracy as a form of government is not uniquely modern or Western, but that consultative forms of government are ancient and global. It can demon­strate how pervasive were early forms of capitalism. Anthropology can also demonstrate how ancient world history itself is: ‘Thales may have been the first Phoenician philosopher to leave a written record; he was certainly not the first to try and conceptualize the world in a general moral and intellectual framework; the precursors of Ogotemmeli, the Dogon sage, did that'. In fact, Goody argues, ‘All societies “placed” themselves in relation to their neigh­bours and sometimes others too. World history, then, is nothing new. All societies had some concept of how they themselves fitted into the wider picture'. (Here, Goody extends the arguments in Chapters 2 and 3 about the universality of world history.) But of course modern world history is very different from the world history of earlier cultures. Above all, it is secular in its approach and (at least in aspiration) less firmly anchored in local cultural or religious traditions.

Both anthropology and world history have attempted to escape from narrowly ethnocentric perspectives. But while world history tended to focus on complex societies, anthropology focused more on small-scale and simpler societies, and, particularly earlier in the twentieth century, it therefore tended to question the more Eurocentric narratives of some forms of world history, and also the related narratives of increasing complexity. Eric Wolf s Europe and the People Without History shows what can be done by systematic­ally incorporating scholarship on the non-literate world into a global account of modern history. So, despite its limitations, anthropology has been a powerful force nudging world history away from the ethnocentric narratives of the nineteenth century or the even earlier narratives of civilizational superiority that go back at least to the time of Herodotus.

The theme of migration is as central within world history as that of gender relations. In Chapter 12, Patrick Manning argues that migration is not merely important; it is a natural, even inevitable theme for world history, because world history is, by definition, about connections. It discourages the study of communities as discrete units. Instead, world history stresses the permeabil­ity of communities, and the many differences that encourage migratory flows. World history also encourages historical study at multiple scales, an approach that is particularly appropriate for a theme as universal as migra­tion. And world history works with an exceptionally wide range of sources, from those of archaeology, linguistics, and genetics to the more conventional written evidence of books and documents; all are powerful tools for under­standing the history of migration. Finally, it's not just people that migrate, but also other species, as well as ideas, religions, diseases, and technologies, so that the study of migration touches on many sub-fields of world history.

While many species migrate, most human migrations are cross­community migrations, taking people (generally young people) from one already existing human community to another. The earliest human migra­tions were probably driven by environmental changes and by social evolu­tion. Paleolithic migrations took our ancestors around the world, into environments where their technologies changed and even, eventually, their body types and skin colours. But even in the Paleolithic, most migrations were not into unoccupied regions, but from one community to another. Agriculturalists migrated in new ways and with different motivations and purposes. Their communities were also larger, which means that scholars can use genetic evidence with increasing precision to track migrations. Horse-based societies in Eurasia engaged in new long-distance migrations as well as new types of annual migrations. Larger networks created new types of communities, including linguistic, religious, and eventually national communities, and often people migrated within the containers provided by these networks. The great migratory movements of Austronesian or Bantu speakers are a reminder of how shared language and culture could shape migratory patterns. Cities also encouraged migrations from villages or small towns in search of work or opportunity; and trade networks by land and sea encouraged the evolution and spread of diaspora communities.

The first global migrations began from the end of the fifteenth century. Some modern migrations, such as the slave trade, were coercive, but most were voluntary, even if driven by economic pressures. In the nineteenth century, steam ships and railways encouraged larger numbers to migrate faster and further than ever before. ‘Where ten million had crossed the Atlantic as slaves from 1550 to 1850, nearly fifty million Europeans crossed the Atlantic from 1840 to 1940, and another eighty million migrants moved from India and China. Two regions of sparse population - North America and Southeast Asia - each absorbed over thirty million immigrants'. These migrations created entirely new communities and diasporas, and increased the salience of racial and ethnic identities within large communities. Many modern migrants were peasants heading to cities in their own or other countries, so it is hardly surprising that by the early twenty-first century, most humans lived in urban areas.

But despite these distinctively modern patterns, we still see ancient pat­terns of migration. Today's cross-community educational migrations are a reminder of the importance throughout human history of migrations by the young away from their home community.

Part ii: The Paleolithic and the beginnings of human history

Part II of this volume surveys the vast period of human history before the appearance of agricultural societies.

There is plenty of room for argument about when the Paleolithic era begins, and different chapters will take different positions. There are really two problems: when the Paleolithic itself begins, and when our own species first appeared. For most paleontologists, the Paleolithic era or the ‘Old Stone Age', begins with the appearance of the first stone tools, over 2 million years ago. Those were made by our Homo habilis ancestors and are generally known as Olduvan because Louis Leakey first identified them in the 1930s in the Olduvai Gorge in Tanzania. However, for historians it may make sense to opt for a narrower definition of the Paleolithic era as that part of the Paleolithic era in which our own species, Homo sapiens, was present. Under that definition, the Paleolithic era really means the Paleolithic era of human history. But this definition raises the second problem of when our species evolved and, as we will see, the answer to that question is disputed. In the chapters that follow, dates for the evolution of modern humans range from about 200,000 years ago to about 70,000 years ago. But whatever date we adopt for the appearance of our own species, or for the beginning of the Paleolithic era, it is clear that the Paleolithic era embraces most of human history.

The Paleolithic era is therefore foundational, however we define it. This is when human history begins. It is in the Paleolithic era that we first find evidence of the behaviours that make our species so distinctive: above all, our cultural and ecological creativity. Ecological creativity meant increasing power over the environment, over landscapes, plants, and animals, and also over other humans. In the Paleolithic era, human ecological power can be measured in the development of new knowledge and technologies that allowed particular communities to occupy new niches until, eventually, our ancestors had spread to every continent apart from Antarctica.

Paleolithic lifeways laid the foundations for the rest of human history, so it is important to know how our ancestors lived. Unfortunately, we lack the fine detail that is available for more recent periods. Nevertheless, there are some important generalizations we can make about the lives our Paleolithic ancestors lived. Most Paleolithic communities were small by later standards. Until the end of the last ice age, most people probably lived in groups of no more than about fifty, with occasional gatherings of larger groups with perhaps several hundred people. Most Paleolithic communities lived by foraging, nomadizing over familiar territories. At the level of the community, we see little change in population densities or in the capacity to mobilize resources. Most communities probably mobilized little more energy and resources than they needed to survive, with a slight surplus for insurance. This means that at the level of the community we do not see evidence of increasing ecological power; we do not see what today we might call ‘intensification'. And that may help explain why it is so tempting to think of the Paleolithic era as technologically and socially stagnant, particularly in contrast to the eras that followed. But as humans entered new niches, the ecological power of humanity as a whole was slowly increasing, and we can measure that increase in human occupation of new environments, as well as in plausible estimates pointing to a slow increase in human populations, particularly after about 70,000 years ago.

As some of the chapters in Part I remind us, Paleolithic lifeways shaped us psychologically, physiologically, and genetically. In some sense, we are still Paleolithic humans today. But of course we should not exaggerate the importance of the Paleolithic. Populations were so small that, of the 80 billion humans who may have lived since our species first appeared (according to the very rough estimates adopted by Massimo Livi-Bacci), fewer than 10 billion, or 12 per cent, lived in the Paleolithic era.^[2] Even if the Paleolithic era is foundational, most human lives (80 per cent according to these same estimates) were lived in the period between the end of the Paleolithic era and 1750. It is appropriate that the allocation of volumes in the Cambridge World History should roughly match these proportions, with one volume out of seven (strictly half a volume) allocated to the Paleolithic era, and one to the era after 1750 (though that volume is a double one).

Though we should not underestimate the technological, cultural, and artistic creativity of Paleolithic communities, nevertheless, human ecological and technological creativity remained fragile and precarious, and was surely accompanied by many periods of retrogression and retreat. It was all too easy for small communities to vanish, along with the knowledge they had used to survive in their home territories. And this is one reason for thinking that forces such as climate change or natural disasters may have played a critical role in human history during the Paleolithic era. Most of the chapters that follow will touch at some point on the importance of climate change in the Paleolithic era.

In Chapter 13, Felipe Fernandez-Armesto offers a broad general survey of the complex relationship between human lifeways and climate change during the Paleolithic era.

Driven partly by debates about global warming, research on ancient cli­mates has been transformed in recent decades, so that it is now possible to explore such questions with a precision unthinkable just two or three decades ago.^[3] As Fernandez-Armesto points out, modern humans emerged during an ice age: ‘We are creatures of cold'. When our species first appeared, the differences between humans and other communities of primates in East Africa would not have been particularly striking. By the end of the last ice age humans already stood out for their range, diversity, adaptability, and the size of their social networks. What were the major changes between these two eras and to what extent were they shaped by climatic changes?

Fernandez-Armesto argues that the most distinctive features of human culture are: ‘relative flexibility in adapting to a variety of environments and relative mutability'. Mutability leaves little room for climatic or environ­mental determinism; indeed we see over and over again that different groups could react in very different ways to similar environmental conditions. Our unique capacity for imagination must be part of the explanation for these differing reactions.

Nevertheless, climate and ecology clearly framed human history through­out the Paleolithic era. At large scales, global climates depend on the Milankovic cycles: changes in the earth's orbit, in the shape of its orbit, and the tilt of the earth's own axis of rotation. In the last million years, these variables have combined to generate a pattern of long cold, dry periods (so-called ice ages) lasting at least 100,000 years, interspersed with shorter warmer ‘interglacials' lasting for approximately 10,000-20,000 years. Other factors, including changes in ocean currents, ensure that within these larger patterns there were many smaller and more erratic changes.

Skeletal remains and genetic evidence both suggest that our species evolved somewhere in East Africa during an ice age, some time between 150,000 and 200,000 years ago. In contrast, the history of recent millennia has been shaped by a period of rapid but erratic warming, from the low point of the last ice age, about 20,000 years ago, until the end of the Paleolithic era, some 10,000 years ago. Between the time of our appearance and the end of the last ice age, our ancestors spread around the world. Why and how?

Modern genetic techniques offer new (if imperfect) ways of tracing these migrations. There were modern humans in the Middle East 100,000 years ago; then a new wave entered the region from about 60,000 years ago. By then there were probably already humans in China and, more remarkably because it implies sophisticated sea-going technologies, by 50,000 years ago humans lived in Australia and Papua New Guinea. Humans entered the colder northern regions of Europe and perhaps even Siberia by perhaps 30,000 years ago and from there, eventually, they reached the Americas, crossing by the ice age land bridge of Beringia, or around its coasts. In the Americas, humans of the Clovis culture hunted to extinction several species of large mammals unfamiliar with humans and therefore not suffi­ciently wary of them. By 10,000 years ago, our ancestors had colonized the planet, and human populations had grown from a few tens of thousands to a few million.

It is a reasonable guess (and at present it can be little more than a guess) that warmer periods encouraged migration because they allowed our ances­tors to occupy regions that had once been uninhabitable. Colder spells surely discouraged or reversed such migrations. Environmental calamities or even warfare may also have encouraged movements into new territories. There has been much debate about the antiquity of warfare, but Jane Goodall's demonstration of something like warfare among groups of chimps makes it difficult to rule out the possibility of violent conflicts. Still, in the absence of hard evidence, most hypotheses about the causes of these migrations remain speculative.

Migrations into new environments surely changed social and gender relationships and cultural ideas. They certainly changed foraging strategies. Despite the difficulties of migrating into the tundra lands of ice age northern Eurasia, hunters living along their southern edges found large, huntable animals whose meat and fat were a rich source of food. Skeletal remains suggest that many ice age hunters were well nourished. Perhaps this explains the aesthetic of the plump female figurines, such as the 30,000-year-old Venus of Willendorf, that are common in late Paleolithic Eurasia. Cave paintings, carvings, and sculptures from late in the Paleolithic era can be found in many parts of the world from Europe to Australia to South Africa. Similarities in late ice age art and technologies suggest the counter-intuitive hypothesis that, despite cultural variations, many aspects of ice age lifeways may have varied surprisingly little as our ancestors spread around the world. Prestige burials, such as the Sunghir burial of 28,000 years ago, from a site near Moscow, also suggest the emergence of embryonic social and economic hierarchies, as some individuals accumulated significant wealth by Paleolithic standards, and even managed to pass it on to their heirs.

At the end of the last ice age, climatic changes were sometimes so erratic that they could trap migrants in new environments and force them to try new ways of exploiting their environments. Some, such as the Natufians of the Fertile Crescent, or the Jomon communities of Japan, became sedentary and built villages. What may have seemed small changes at the time were harbingers of a revolutionary transformation in human lifeways.

In Chapter 14, the first of two linked chapters on the Paleolithic era in Africa, Chris Ehret takes up the thorny issue of when modern humans first appeared. Ehret, a specialist in the history of languages as well as in the archaeology of Africa, has modern humans appearing later than some other authors in this volume. ‘Before about 48,000 years ago', he writes, ‘human history was African history'. True, there are signs of modern-looking humans in the Levant from about 100,000 years ago, during a relatively warm period. But their disappearance and replacement by Neanderthal populations as climates deteriorated over the next few millennia suggest that they lacked the creativity of later human groups, some of which would leave Africa 50,000 years later. The distinction Ehret draws between archaic modern humans and fully modern humans provides the basic periodization for Chapters 14 and 15.

Not until about 70,000 years ago, Ehret argues, did fully modern humans evolve, and they evolved somewhere in East Africa: ‘the full package of modern human capacities took shape between about 70,000 and 48,000 bce [that is, 50,000 years ago]'. By 50,000 years ago, groups of modern humans began to migrate into other parts of Africa, and also into Eurasia and beyond. Everywhere, they encountered, and eventually displaced, groups of more archaic hominins. The groups they displaced still had technologies typical of the ‘Middle Stone Age' (or ‘Middle Paleolithic' in the terminology used in the archaeology of Eurasia), and probably lacked modern human linguistic abilities. In Africa, though, the differences between archaic and modern humans were probably less marked than in Eurasia, which may be why we find evidence of different groups coexisting for long periods of time.

Sudden technological changes provide one form of evidence for Ehret's periodization. In Africa, archaeologists have found relatively sudden transi­tions from the prepared-core stone technologies typical of the Middle Stone Age to more modern technologies characterized by carefully made small blades and tools made from small flakes and often associated with bone tools and art. Where skeletal remains survive, we find fully modern remains associated with modern technologies, and archaic skeletal remains with Middle Stone Age technologies. Skeletal remains also suggest that the modern form of the human pharynx, which is necessary to articulate the full range of sounds used by modern human language, only appeared after about 70,000 years ago.

The period about 70,000 years ago is particularly significant because genetic evidence suggests that human populations shrank to perhaps just 10,000 individuals. The cause may have been a sudden climatic deterioration caused by the eruption of Mt Toba in modern Indonesia about 72,000 years ago. But it is also possible that the impression of a demographic bottleneck actually arises from rapid growth in the populations among which modern human languages first appeared. Linguistic evidence provides some support for this idea. Modern linguistic studies show a clear linguistic trend away from complex consonantal systems as one moves outward from eastern and southern Africa; this suggests that all modern languages may derive from an original language that appeared about 70,000 years ago in East Africa, and was characterized by exceptional consonantal complexity. Genetic evidence also points to the importance of East Africa, for here and only here do we find all three of the major genetic groupings into which all contemporary humans fall. Here, too, we find evidence for new types of stone points that may have been used for projectile weapons, perhaps even for early bows and arrows. In addition, rock art suggests the presence of new forms of religious beliefs similar, perhaps, to some forms of shamanism. Modern forms of language may also have allowed the emergence of larger communities and networks, held together by more complex kinship systems.

Taken together, this evidence suggests a late evolution of fully modern humans with modern forms of language, followed by a slow accumulation of new skills, new social relationships, and new cultural forms. The consoli­dation of these new communities was slow and fitful. In the Howiesons Poort culture, for example, which dates from about 63,000 years ago, we find evidence of fully modern industries lying between layers of more archaic technologies. This suggests a slow ebbing and flowing of different cultural traditions. It also suggests that the advantages did not always lie with fully modern humans. But by 50,000 years ago, there is evidence of fully modern human communities from southern parts of East Africa all the way up to the Red Sea. From here, some modern humans would eventually enter Eurasia, where their appearance created the impression of a sudden transition to modernity. Others would move to other parts of Africa where they would slowly displace communities of archaic hominins.

In Chapter 15, Chris Ehret takes the story of human evolution in Africa up to the end of the Paleolithic era. From about 50,000 years ago, he writes: ‘a new era in human history began'. Modern humans began to spread from East Africa through the Levant and north into Europe and Eurasia or eastwards through South Asia and to Australia. They also spread to the south, west, and north within Africa. Over more than 30,000 years, fully modern humans slowly displaced more archaic groups still characterized by Middle Stone Age cultures. However, in some parts of West Africa, Middle Stone Age cultures survived until the end of the last ice age.

From about 50,000 years ago we find evidence of fully modern technolo­gies spreading southwards from East Africa into Botswana and parts of modern South Africa. But instead of a rapid displacement, the evidence suggests that modern and archaic cultures coexisted here for as long as 20,000 years. Modern cultural traditions also spread westwards; by 30,000 bce Later Stone Age technologies have reached western Cameroon, but they seem not to have reached West Africa. Moving northwards, some groups of fully modern humans seem to have reached the Levant by 50,000 years ago, presumably through Egypt. So, by the Late Glacial Maximum, modern humans could be found in much of eastern, northeastern, and southern and Central Africa, but not yet in West Africa. Humans using Middle Stone Age industries survived alongside them in parts of southern and Central Africa ‘although probably in declining numbers'.

The Late Glacial Maximum dates from approximately 22,000 bce and lasted several thousand years. It brought cooler and drier climates and periods of rapid climatic change that accelerated change throughout Africa. From this time on, linguistic evidence based on the comparative study of modern languages begins to offer intriguing hints about lifeways, kinship structures, and even religious traditions.

Surviving Middle Stone Age populations vanished in the south, centre, and northwest of the continent at about the Glacial Maximum. In East Africa, a new Later Stone Age culture appeared soon after the Glacial Maximum. This may have been associated with early speakers of Khoesan languages. Two distantly related Khoesan languages are still spoken in the region, while the earliest Khoesan languages seem to have included words for bows and arrows and for arrow poisons, evidence that aligns well with the culture's archaeology. Rock art from the region also fits with what is known of ancient Khoesan religious traditions. In the Congo Basin, distinctive traditions emerged in the ‘Batwa' cultural complex associated both with rock art and new stone industries. These traditions may well have been ancestral to peoples of the modern ‘Batwa' tradition.

The northeast of Africa is the homeland of three of Africa's major lan­guage families: Nilo-Saharan, Afrasian (or ‘Afroasiatic'), and Niger- Kordofanian. Such cultural fecundity suggests the presence of large popula­tions near the headwaters of the Nile at and after the Late Glacial Maximum. From about 13,000 bce, evidence begins to appear, particularly along the Nile, of semi-sedentary communities harvesting and grinding wild grains. These cultures may reflect the arrival of Afrasian-speaking peoples, some of whom would eventually bring the ancestors of the Semitic languages into the Levant region.

In West Africa, Middle Stone Age industries survived as late as 13,000 bce. Then they vanished, to be replaced by Later Stone Age technologies brought, in all probability (the archaeological record is thin), by speakers of Niger- Kordofanian languages from the region of modern Sudan. Here, probably during the cold Younger Dryas, we begin to see early evidence for the cultivation of wild grains and even for early forms of pottery, apparently for cooking. Meanwhile, in the eastern Sahara evidence begins to appear in the ninth and eighth millennia bce for the earliest forms of cattle herding in world history, as well as the cultivation of gourds and grains. As Ehret concludes: ‘Africa at the beginning of the Holocene was not a place apart. The same trajectories of human change were emerging in Africa as in several other parts of the world - toward agricultural ways of life and, much farther off in time, toward more complex and more unequal societies'.

In Chapter 16, John Hoffecker discusses the Paleolithic era of Europe. Like Fernandez-Armesto and Ehret, he insists that the challenge is not just to find human-like remains, but also to find evidence of distinctively human behav­iours. Hoffecker's epigraph cites V. Gordon Childe, who argued that archae­ologists study ‘the fossilized results of human behavior'. As Hoffecker argues: ‘It is the origin of the mind... that is the central issue in human evolution. It is not only the immense quantity of non-genetic information that modern humans collect and store, but it is their capacity for creating novel structures or arrangements of that information that render them unique among living organisms'.

Europe's role in the Paleolithic era is distinctive in several ways. First, the region is geographically distinct. It is separated from Africa and the Near East by the Mediterranean, the Black Sea, and the Caucasus Mountains, while its western regions are warmed by Atlantic Ocean currents that gave it a benign climate and a richer mix of species than lands to its east. Second, European archaeology is distinctive, so distinctive that for a long time its traditions warped our understanding of the Paleolithic era. Europe was the home of modern forms of science, and it was here that some of the earliest studies of human evolution were conducted. By the late nineteenth century, enough fossil remains and stone artefacts had been found for Sir John Lubbock to announce the existence of a distinctive ‘Palaeolithic' era in human history. His period would eventually be divided into an Upper Paleolithic, associated with modern humans, a Middle Paleolithic, associated with Neanderthals, and a pre-Neanderthal Lower Paleolithic. European scholars so dominated early attempts to describe human evolution, and the Paleolithic evidence from Europe was so rich and so diverse that it seemed natural to assume that our species evolved in Europe. Only in the twentieth century has it become clear that the ancestral home of our species was really in Africa.

Before 2.5 million years ago, our ancestors were ‘small-brained “bipedal apes”' living in Africa. The larger-brained Homo genus appeared about 2.5 million years ago. By 2 million years ago, some members of the genus had become the first human-like creatures to enter parts of Eurasia, though none of these early migrants travelled further north than c. 40°. These early migrations were temporary and occasional, and depended on stone tool technologies similar to those of the African Lower Paleolithic. Simple stone tools make it possible to butcher large animals, which increased the con­sumption of meat, and that may be why these early forays into cooler regions were possible. The earliest evidence of migrations into western Europe are the Homo remains from Atapuerca in northern Spain dated to just over i million years ago.

From about 600,000 years ago, we find a new species, Homo heidelbergensis, migrating from Africa into Europe, probably around the eastern Mediterra­nean and across the Bosporus. Heidelbergensis was the ancestor of both Neanderthals and modern humans. Their brain size overlapped with that of modern humans, they clearly controlled fire, and they made more com­plex and more sophisticated stone tools than their erectus predecessors. By 500,000 years ago, they could be found in England at the important site of Boxgrove. The important German site of Schoningen dates to c. 400,000 years ago and is one of the first Paleolithic sites to contain wooden artefacts including spears.

Conventionally, the Middle Paleolithic in Europe begins with the appear­ance of Neanderthals. Neanderthals evolved in Europe from heidelbergensis ancestors at least by c. 250,000 years ago. They were apparently well adapted to glacial conditions because, unlike other hominins, they were able to remain in Europe even in periods of extreme glacial climates. Analysis of Neanderthal bones shows that they depended largely on meat from large herbivores such as mammoth. Surprisingly, though, there is no evidence of sewn clothing or of the ability to make fire, though there is plenty of evidence that they could maintain fires. Their stone tools, however, were sophisticated, and have long been used as a marker for the beginning of the Middle Paleolithic, from about 300,000 years ago. It has recently been shown that Neanderthals could also make composite tools with multiple parts that were joined using sophisticated adhesives. Unfortunately, we have little understanding of the Neanderthal mind. They probably buried some of their dead, though that in itself is not necessarily proof of belief in an afterlife. Though they possess the FOXP2 gene, which seems to be important for human speech, the objects they made changed little over 200,000 years, which suggests that they lacked the rich creativity associated with modern human languages.

The Upper Paleolithic in Europe is conventionally (if somewhat anachron- istically) associated with the appearance of our own species, Homo sapiens. The evidence is now overwhelming that modern humans evolved in Africa. Some members of our own species appeared in Europe about 50,000 years ago and Neanderthals may have vanished within 10,000 years of that date. There is now clear evidence of some interbreeding between the species, probably about 100,000 years ago when modern humans and Neanderthals lived near each other in the Near East. But the differences between the remains left behind by modern humans and Neanderthals are immense and significant, and they almost certainly arise from the appearance of modern human language: ‘a fully syntactic language with phrase structure grammar and potentially infinite variety of sentences and narratives'. This change, Hoffecker argues, marks the ‘advent of the modern mind'.

Modern humans reached Europe from the Near East, through the Cau­casus or across the Bosporus and probably during a warm period. From 42,000 years ago we find evidence for proto-Aurignacian industries, showing the sort of diversity clearly characteristic of modern humans. Remains include eyed needles and hare traps, as well as rich artistic products, includ­ing an ivory carving, the Lowenmensch from Germany, which seems to depict a semi-human figure of myth. Some of these cultures are associated with an extremely cold spell, suggesting that modern humans rapidly developed technologies appropriate for glacial conditions.

Evidence for technological innovation multiplies between 30,000 and 25,000 years ago, in the Gravettian period. Large settlements in Central and Eastern Europe suggest improved food-producing technologies, and some sites contain ovens hot enough to make ceramics. The extreme cold of the Late Glacial Maximum forced the abandonment of many more northerly sites, as ice sheets spread over large parts of northern Europe for several thousand years. Then, after 20,000 years ago, more northerly sites were re-occupied by representatives of the Magdalenian and EpiGravettian cultures. By 12,000 there is evidence of large partly permanent settlements, some with houses made of mammoth bones. Here, as in the Near East, China, and parts of North Africa, we see cultural and technological changes that hint at the early stages of a shift towards agriculture.

In Chapter 17, Robin Dennell describes Paleolithic migrations into Asia, which also began in Africa and passed through the Near Eastern bottleneck. Like Hoffecker, Dennell stresses the importance of climate change in shaping the history of the Paleolithic era. Dennell's chapter tells a story of two major hominin dispersals: Out of Africa ι (the most ancient hominin dispersal, from almost 2 million years ago); and Out of Africa 2 (the dispersal of Homo sapiens within the last 100,000 years).

The earliest evidence of hominins living outside of Africa has been found at Dmanisi, Georgia, where the remains of early forms of Homo erectus have been found, and dated to 1.77 million years ago. Though their brains were about half the size of those of modern humans, their use of stone tools suggests increasing dependence on meat and marrow in their diets. Indeed, these technologies, which presumably gave access to more food energy, may explain the first dispersals outside of Africa. Other early finds in Asia include skeletal remains in Sangiran, Java, from c. 1.5 million years ago; and hominin artefacts from north China, dated to about 1.66 million years ago. Coupled with evidence from Atapuerca in northern Spain, from c. 1.3 million years ago, these show that hominins could be found throughout Eurasia to a latitude of about 40° North by about 1.5 million years ago. But, as Dennell points out, the evidence is so thin that a single find, or a slight improvement in the precision of dating techniques, could easily force us to re-think both the geography and the timing of these early dispersals. It is also clear that the existing evidence provides a tiny sample of multiple dispersals and retreats, including perhaps reverse dispersals back into Africa.

The story of Out of Africa 2 is the story of our own species, Homo sapiens, and its dispersals from Africa. There is a broad consensus that remains dated to 190,000 years ago from the Awash Valley in Ethiopia belong to Homo sapiens. Modern human remains are first found outside of Africa in modern Israel, where they date to about 125,000-70,000 years ago; but this population seems to have been displaced by Neanderthals some time before 70,000 years ago, presumably as a result of climatic deterioriation. Between 40,000 and 60,000 years ago there were new dispersals of modern humans from Africa. These took our ancestors to Southeast Asia, New Guinea, and Australia. The earliest evidence of these dispersals is associated with Middle Stone Age technologies similar to those of Neanderthals, and based on the removal of flakes from specially prepared cores. Like the Out of Africa 1 story, this story also rests on limited evidence, and could easily be transformed. For example, the discovery of new skeletal remains in the Levant and Southeast Asia before 125,000 years ago would suggest (as Peter Hiscock will argue in Chapter 18) that there may have been a successful earlier dispersal of modern humans from the Levant to South and Southeast Asia.

As evidence of ancient climate changes improves, it is tempting to link what we know of early human dispersals to the erratic climate changes of the ice ages. There were large cycles of change driven by the Milankovic cycles, but also shorter, more erratic, and more abrupt changes such as the ‘Heinrich' events: cold snaps that could last for centuries or even millennia. In warmer and more humid periods, human populations could settle further north, while in colder and drier periods, populations probably contracted south and some groups may have been isolated from other populations for long periods. This means that there must in practice have been many different periods of advance and retreat, few of which have left behind direct evidence. In Tajikistan in Central Asia, we have direct evidence that modern humans arrived only in warmer periods, and evidence from China and Britain hints at similar patterns.

Changing technologies also shaped early hominin dispersals. Stone tools, which gave humans access to a meat-rich diet, probably enabled the earliest migrations into colder regions. As Chapter 8 argues, a meat-rich diet com­bined with a shrinking of the human gut may also help explain the rapid increase in brain size in the last few million years. And, as brain size correlates closely with group size in most primates, larger brains may imply larger social groups, more sharing of information, and the evolution of a ‘social brain' that ‘would have widened the potential scope for hominins to disperse into new types of environments, or to utilise them more effectively'.

In Asia, the impact of new technologies is most apparent in the last 50,000 years. We see little evidence for any widening of the hominin range over a million years; then, within the last 50,000 years, the range widens fast. Siberia was probably colonized from 40,000 to 50,000 years ago, bringing humans to the ice age land bridge of Beringia from which some would eventually cross into the Americas. Australia was colonized at least by 50,000-60,000 years ago (Peter Hiscock will give evidence for even earlier dates in Chapter 18), and Japan by 40,000 years ago. Both these dispersals required significant navigational skills. Rainforests of Southeast Asia were also occupied by 40,000-50,000 years ago. Finally, the Tibetan Plateau was occupied right at the end of the last ice age. The evidence from Asia, then, points to a very significant inflection in the human history of Asia from about 50,000 years ago, with the arrival of modern humans.

In Chapter 18, Peter Hiscock surveys recent evidence on the history of Australia in the Paleolithic era. During cooler periods of the ice ages, sea levels were low enough for Australia, New Guinea, and Tasmania to be linked within a single Paleo-continent, known as Sahul, that was separated from the ice age peninsula of Sunda/Indonesia by deep water.

Debates about the earliest colonization of Australia affect how we inter­pret the earlier migrations of modern humans out of Africa. The dominant model has modern humans leaving Africa as late as 60,000-65,000 years ago, and assumes that finds of modern humans in the Near East before 90,000 years represent a ‘false start' (an interpretation we have encountered already in Chapters 14, 16, and 17). This model requires rapid migrations through South Asia to Australia if it is to fit with the best dates for the colonization of Australia. For example, it has been suggested that we should imagine a migration of peoples who stayed close to the coasts, exploiting coastal resources and developing their sea-going skills en route to Australia. The late dispersion model also encouraged scepticism about any dates for Austra­lian settlement earlier than about 45,000 years ago.

Hiscock argues that recent evidence undermines the late dispersal model. Genetic research suggests that human mutation rates may have been slower than has often been assumed, which is consistent with alternative models in which Australian populations diverged from African populations as early as 120,000 years ago. Perhaps early migrations from Africa were not false starts, but the beginnings of successful dispersals that have left little trace. Recent genetic evidence also points to genetic exchanges (analogous to those in Europe with Neanderthals) between modern humans from an early disper­sal, and populations of other hominin species, including the Denisovan populations just identified in 2010 from remains in a Siberian cave whose ancestors had left Africa over half a million years ago. This allows the possibility that, instead of racing from the Near East to Australia, the populations whose descendants eventually colonized Australia may have ranged widely within Eurasia in a more leisurely dispersal before reaching Australia. The absence of Denisovan genes from modern East Asian popula­tions also suggests that Australia was colonized by an earlier wave of modern humans, and East Asia by a later wave that displaced Denisovan populations. Finally, the presence of similar genetic lineages in both modern and ancient Australian populations suggests that most modern indigenous Australians are descended from a single early wave of colonization.

An early dispersal model aligns well with archaeological evidence suggest­ing that humans had arrived in Australia at least by 50,000-60,000 years ago. Rock shelters in Arnhem Land in northernmost Australia contain artefacts that have been dated (by thermoluminescence) to as early as 67,000 years ago. Though such early dates have been questioned, there is firm evidence that humans were present in many parts of Sahul by 50,000 years ago, and to have spread so widely they must have arrived well before that date.

The earliest human skeletal remains in Australia come from Lake Mungo in southern Australia and date to about 43,000 years ago. Mitochondrial DNA extracted from a Lake Mungo skeleton is similar enough to modern Australian Aboriginal DNA to show that they belong to the same lineage, which suggests that there were no major colonizations after the founding wave. By 45,000 to 55,000 years ago, humans already occupied a great variety of environments, including sandy and rocky deserts, semi-arid grasslands and savannahs, as well as uplands, tropical regions, and woodlands, and there is plenty of evidence for distinctive regional cultures. The disappearance of many large-bodied species at about the time of the arrival of humans may have been a result of human over-hunting; though the absence of kill sites (in contrast to the Americas, where they are abundant) weakens such interpretations. A period of cooler, drier climates may also have played a role in these extinctions. Whatever the cause, the removal of many large herbivores must have transformed the environment. For example, it would have allowed the accumulation of large amounts of fuel and increased the likelihood of natural firing of the land.

From about 45,000 years ago, until the Late Glacial Maximum, Sahul underwent a ‘great drying'. Sea levels dropped, exposing new exploitable regions along the continent's shorelines, while the interior became drier and many lakes vanished. Changing conditions generated new technologies, some adapted to dry conditions, some making use of ground seeds. Evidence of long-distance exchanges, over many hundreds of kilometres, suggests the importance of extensive networks in drier environments.

Between 25,000 and 18,000 years ago, during the Late Glacial Maximum, oceans dropped to 125 metres below their current level and climates became exceptionally dry and cold. Glaciers formed in some upland regions and the land area of Sahul reached its largest extent. Many older archaeological sites were abandoned, and even bodies adapted, becoming larger and more robust than the bodies of later populations.

From about 19,000 to 10,000 years ago, climates began to warm erratically and sea levels began to rise, from 125 metres below today's sea levels to just 20 metres below 10,000 years ago. Australia's land area shrank by a third. Along Australia's northern borders, shorelines retreated as much as 1,000 kilometres as once occupied lands were drowned, forcing groups to migrate and re-arrange their territories. Tasmania was separated from the mainland, as was New Guinea. The changes of this period were so erratic that ecologies seem not to have stabilized until the Holocene; and not until the last 3,000-4,000 years were climates stable enough to allow more specialized and intensive systems of exploitation to emerge, systems that may parallel developments in the Near East before the first appearance of agriculture.

In Chapter 19, Nicole Waguespack describes the Paleolithic colonization of the Americas: a landmass even larger and more varied than that of Australia. Humans reached the Americas through the harsh environments of northeastern Eurasia, which explains why the Americas were occupied after the Late Glacial Maximum. Even if Siberia was colonized temporarily from as early as 40,000-50,000 years ago (Chapter 17), more permanent Siberian settlements appear only c. 18,000 years ago. At the Late Glacial Maximum, North America's major ice sheets may have merged, blocking movements from Beringia southwards. But after the coldest period a corridor opened between major ice sheets, which may have allowed travel along the Yukon and McKenzie River Valleys into the Americas. Colonists may also have moved through Beringia and around the Pacific coastline.

There is little doubt that humans entered the Americas from northeastern Siberia, or that some had arrived by 14,500 years ago. However, evidence on the founder populations is thin enough to generate heated debates about the exact chronology and geography of their arrival. Many forms of evidence show that the first human communities in the Americas were highly nomadic and dispersed over large areas, and this itself may explain the scanty arch­aeological record they left behind. It also makes it likely that many groups left no trace at all; sporadic traces of such groups may help explain the large number of claims for earlier arrivals. Sites that might eventually provide evidence for occupation before 15,000 years ago include Monte Verde in Chile, Pedra Furada in Brazil, and Meadowcroft in Pennsylvania and Butter­milk Creek in Texas in the USA.

Before the 1920s, it was still possible to argue either that the Americas were occupied very recently, or that human occupation was as ancient as in the Old World. The discovery of Paleolithic sites in the western United States, beginning with the Folsom site in 1927, provided the first clear evidence of early human arrivals. From the middle of the twentieth century, radiometric dating helped clarify the chronology of American sites. The earliest period of human occupation of the Americas is now described as Paleoindian. Cultural, social, and technological continuities explain why that period extends into the Holocene, ending with the appearance of new tool kits, and signs of sedentism during the period known as the Archaic, which conventionally begins from about 8,000 bce.

American Paleoindian cultures were highly mobile and produced distinct­ive stone tools. The best known Paleoindian cultural tradition is the Clovis tradition, named after a distinctive type of projectile point first found near Clovis, New Mexico. Up to 4,000 similar points have been found in an area reaching from Canada to Mexico, often in association with the remains of large herbivores such as mammoth. Most date from within about 600 years of 13,500 years ago. These and the later Folsom stone points are the only known stone tool traditions with fluted points. Most Clovis sites are kill sites, sometimes associated with camp sites. Many signs point to the mobility of Clovis foragers; they include the absence of large grindstones and the presence of tools made from stone quarried hundreds of kilometres from where they were found. High mobility may help explain why the first populations in the Americas rapidly colonized large areas.

As in Australia, the arrival of efficient hunters in a continent whose megafauna had no experience of humans may help explain the disappearance of many of their species from about 13,000 years ago. We know that Clovis peoples hunted megafauna, and we also know that large species are vulner­able to over-hunting because they reproduce slowly. But, as in Australia, it is also possible that rapid climate change played a role in the disappearance of many species of megafauna. The sudden cold snap of the Younger Dryas coincided quite closely with America's megafaunal extinctions.

The hypothesis of a rapid spread of highly mobile Clovis peoples through­out the Americas, which dominated thinking from the 1930s to the 1960s, has recently been questioned. Some archaeologists see Clovis cultures as an inland development, quite distinct from other colonizing groups that special­ized in shoreline resources and moved along coastal routes that we no longer see because they were drowned as sea levels rose at the end of the ice age. The paucity of skeletal remains from this period adds to the difficulty of clarifying such issues; at present early Paleoindian cultures are represented by the remains of fewer than ten individuals. As with much of the archae­ology of the Paleolithic era, the available evidence is sparse enough that a single discovery could transform our understanding of the early colonization of the Americas.

As the chapters in Part II of this volume demonstrate, the Paleolithic history of our species is coming into sharper focus, and that makes it more important to integrate Paleolithic history more fully within modern world history scholarship, teaching, and research. New techniques, including radio­metric dating, genetic comparisons, and increasingly precise ways of tracking climate change, have allowed the construction of a clearer account of the vast periods of time between the evolution of our species and the emergence of agricultural societies early in the Holocene Epoch. As we have seen, dates for the evolution of fully modern humans are still contested; the dates adopted in this volume range from almost 200,000 years ago to as late as 70,000 years ago. The chapters in this volume also differ on the significance of early human dispersals from Africa. Modern humans seem to have been present in the Levant 100,000 years ago, but precisely how modern were they? And was that dispersal a false start, or the first step in migrations that eventually led our ancestors into much of Europe, Asia, and eventually Australia? But if the precise chronologies are contested, the main lines of the story are now much clearer than they were a generation ago. We are an African species; but our ancestors displayed such ecological and technological creativity that they were able to occupy lands in all the continents apart from Antarctica by the end of the Paleolithic era. The remarkable and distinctive history of our species begins deep in the Paleolithic era. But we can also see that the migrations themselves came in pulses, only some of which are visible in the archaeological record. Those pulses were shaped, in part, by climate change. During colder, drier phases, deteriorating climates checked and even reversed migrations, and inhabited regions were abandoned, often to be re­occupied, sometimes with new technologies, once conditions improved. The migratory pulses were also shaped by our ancestors' technological creativity and by the slow accumulation of new techniques and new ecological and social understanding, so that, despite the checks and reversals, our ancestors eventually occupied environments ranging from tropical forests to the tundras of Siberia and North America. These Paleolithic movements laid the foundations for everything that would follow in the Holocene history of our species.