The "Landing of Columbus" from the Rotunda of the United States Capitol.

The last half century has not been kind to Christopher Columbus. Drawing on a study of exhumed skulls from fifteenth-century Europe, an article in the most recent Yearbook of Physical Anthropology found that syphilis, first diagnosed in Europe in 1495, was carried back to the continent by Columbus' crew. Within a decade, the bacterium had spread to European soldiers in India, who then infected Asians, making syphilis the first global epidemic. Once the great explorer, Columbus was now just an agent of venereal disease.

Columbus has long stood at the center of debates about globalization: when and how it began, and who it has helped and hurt in the five centuries since he made landfall in 1492. His discovery of the Americas was central to the process of integration and growing interdependence of the various parts of the world, one that continues to this day.

For many years, historians and the public viewed Columbus as a visionary, a heroic discoverer, and a defier of orthodoxy. In the 1960s, however, the prevailing academic view of the Genoese mariner became less flattering. Columbus was slathered with blame for all the destruction that followed in his wake: tens of millions of Native Americans dead and another ten million Africans enslaved. Yes, Columbus connected the hemispheres and ushered in the modern world, but the benefits accrued mainly to Europeans. Revisionist historians, such as Kirkpatrick Sale, captured this mood. Sale's popular 1990 account, The Conquest of Paradise, argued that Columbus spearheaded a campaign to plunder and destroy the Edenic world of the Americas. Instead of celebrating the 500th anniversary of the American landfall, Sale and others lamented it, echoing the growing public discontent with globalization itself.

Among scholars, the simplistic debate over whether Columbus was good or bad has become considerably more nuanced. The full significance of 1492 for global history -- and the history of globalization -- has come into ever-sharper relief. Historians now focus more on the role that native peoples played in the course of European expansion and conquest, treating them less as passive victims and more as active participants in global integration.

There has been a broader shift, too. Instead of seeing the discovery and colonization of the Americas as just one in a series of discoveries and breakthroughs, a school of thought now identifies 1492 as the central pivot of world history. The first popular book to do this was the scientist Jared Diamond's 1997 bestseller, Guns, Germs, and Steel, which tried to explain how Europeans came to dominate the world -- how they came to possess lethal technologies and biological immunities. For Diamond, the conquest was more or less inevitable, and the effects of the clash less important than its course.

It is against this backdrop that the journalist Charles Mann has written two major books that, more sharply than any others, ask how 1492 shaped the subsequent centuries of global integration. The conquest of Native American worlds is not his subject. It is rather the conquest's effects and legacies, including lessons that Native Americans and their descendants can teach the rest of us about the use of resources. Native Americans may have been victims. But whereas Diamond saw them as doomed because of their technological backwardness, Mann reveals that they had accumulated a staggering amount of knowledge on the eve of the conquest. Their indigenous innovations triggered an economic bonanza and kicked off what we today call globalization.

NATIVE AMERICA'S GOT TALENT

What did the world look like before 1492? This is the question Mann asks in 1491, which depicts the Western Hemisphere before it was inducted into global trade and immigration. Mann, a popular science author, has written several books on the intersections of science, technology, and commerce. Standing aloof from academic squabbles, he is able to put scholarly findings in perspective, free of insider jargon. Mann brings science to life through his narratives of discovery; his heroes are the anthropologists, archaeologists, and demographers who shatter received wisdoms about the past by applying their tools to anomalies and unexplained histories.

Mann seems to get particularly excited when the discoveries debunk the textbooks he was raised on, such as William McNeill's 1967 A World History, which ignored the Americas when charting the wellsprings of civilization. Mann forgives McNeill for reflecting the conventional wisdom of his day, which explained the so-called rise of the West as the result of an endogenous European capacity for progress. But he has no patience for the historians who commit the same oversight in his son's textbooks several decades later. "The thesis of the book in your hands," he tells readers, "is that Native American history merits more than nine pages."

Mann's books invite readers to picture the past differently. He asks them to imagine flying over the urban sprawl of Tiahuanaco, in modern-day Bolivia, one of the oldest metropolises of the ancient Andes, or to examine from a height the farm of Dona Rosario, a descendant of runaway slaves in Brazil. These snapshots of the New World show how nature was ordered, resources organized, and property tended. What may look ramshackle or dilapidated from one angle makes good sense from another.

From such unusual vantage points, Mann builds an unusual counternarrative about the Americas before the conquest. Where Diamond stressed some basic differences between peoples (their technological prowess, their biological immunities, their cultures of warfare), Mann emphasizes human commonalities. For instance, he argues that Eurasians and the original Americans were not so different in the way they dealt with nature. Mann wants to bury the myth of the New World as a pristine Eden where people lived suspended in time, incapable of turning nature into their garden. The conquistadors often justified the devastation they wrought by proclaiming that the defeated were simply part of nature, not its masters. Ironically, centuries later, purportedly progressive environmentalist authors, such as Sale, would similarly argue that, in Mann's words, Native Americans lived "in a spiritual balance with Nature." Mann shows that Native Americans were in fact something very different, and in that sense familiar: inventive people who molded the world around them.

To make this case, Mann turns to demographers and archaeologists, such as Henry Dobyns and William Denevan, whose recent research has confirmed that pre-Columbian civilizations exploited nature to support large, densely populated, urbanized societies. Whereas in the early 1960s, the prevailing view was that the New World had only a few million people when the Spanish arrived, nowadays the more accepted figures are between 40 million and 80 million; some scholars argue the population may have reached 200 million.

In order to sustain such large numbers and such immense cities as Cahokia (in today's midwestern United States) and Tiahuanaco, the original Americans had to do more than pick berries; they had to transform their environment. Mann demonstrates this by invoking recent findings that the first Native Americans crossed from Siberia to Alaska earlier than was traditionally thought, perhaps as far back as 25,000 years ago. They thus had time to develop their own techniques for shaping the virgin landscape. In central Mexico, Native Americans devised a complex system of hydraulic engineering. At a time when Europeans were still counting with their fingers, the Olmec had already invented the number zero. By 3000 BC, there were fully 25 complex cities in the New World. And Mann speculates that before Columbus arrived, up to two-thirds of what is now the continental United States was covered in fields, with much of the Southwest terraced and irrigated.

Europeans, in short, were not the only ones who laid waste to the Americas; so did the Native Americans. But Mann makes the case for a particular Native American approach to the environment and the use of natural resources that people today would do well to study and possibly emulate. In the thousands of years it took for the Native Americans to adapt to their environments, they devised strategies to make exploitation sustainable. Consider the Amazon, which would be a wet desert if cultivated like a European farm because intensive tillage would deprive the weathered, acidic soils of the energy they need. Native Americans turned this rainforest into an arable frontier capable of feeding millions.

The European conquest did not entirely bury the evidence for this alternative model of resource husbandry. Asked to write a magazine article in the 1980s on the battle over Pacific Northwest salmon, Mann found proof that Native Americans in present-day Oregon had long ago figured out how to extract fish in large numbers without killing them off. Their descendants have continued the practice. So Native Americans were, and to some extent remain, the champions of a balanced method of extracting resources. Their lesson for today is not that one should give up on technological progress and become subject to the land. It is that one can master the land without sowing the seeds of its destruction.

UNFAIR TRADE

In 1491, Mann showed how Native Americans, like Eurasians, harbored ancient traditions of innovation and remade their surroundings. But there was a fundamental difference. In the Eastern Hemisphere, inventions spread quickly through trade, and in doing so, they spurred new technologies. The western half of the globe saw very little, if any, traffic between its hubs of human improvement.

All societies, Mann insists, miss technological breakthroughs and have blindspots that can be bridged by traffic in ideas and goods. The problem for Native Americans before 1492 was that they were cut off from African, Asian, and European discoveries -- and even innovations on their own continent -- that could have filled those gaps. Lacking seaworthy craft or effective beasts of burden (the llama is a prickly porter), Native American communities were largely unable to travel, and so most became inward-oriented.

Mann's sequel, 1493, is an account of the Americas and globalization: how trade and immigration, kicked off by Columbus, transformed the New World, and how the New World, in turn, remade the old one. The idea of a Columbian exchange comes from one of Mann's scientific heroes, the environmental historian Alfred Crosby. Crosby's revolutionary 1972 book, The Columbian Exchange: Biological and Cultural Consequences of 1492, focused not only on the humans who traveled between the Old and New Worlds but also on the diseases (smallpox to the Americas, syphilis to Eurasia), crops (sugar went west, potatoes went east), and animals (pigs tore through the American underbrush with predator-free abandon) that accompanied them. This exchange was the most important ecological event in the planet's history since the death of the dinosaurs. Crosby overturned a long-standing academic tradition of seeing the integration of the hemispheres as flowing one way, from Europe to the Americas. He also helped tear down the view that progress and economic growth were endogenous to Europe.

Even the victims of Columbus' landfall contributed to the welfare of Eurasians. Centuries of Native Americans' genetic improvements to maize and potatoes, for example, let the rest of humankind extract more calories per acre. Although the Native Americans themselves were nearly wiped out by diseases brought by Columbus and his followers, in the centuries after 1492, the rest of the world's population began to climb steadily. By laying waste to the Americas, Europeans acquired the means to rebuild their own societies, which had been decimated by medieval plagues and invasions. Along the way, of course, they spun tales of having discovered "natural man" living in the unspoiled forest.

For the past four decades, historians have been living in the shadow of The Columbian Exchange; indeed, Crosby remains the dominant character of 1493. This may explain why the publication of Mann's sequel has made much less of a splash than did 1491; the gist of the argument and much of the evidence are so familiar. Old World crops, such as coffee and sugar, made such places as Brazil and Cuba possible. As parasites killed off the locals, Europeans enslaved Africans, who became a new source of labor. Drawing on Crosby, Mann terms the years following 1492 a "nascent Homogenocene" -- a biological era of increasing homogenization -- because the conquest created the conditions for the mixing, swapping, and blending that have yielded a more biologically uniform planet. Still, although 1493 is less of a concept buster than 1491, it does illuminate the full extent of the exchange, adding recent empirical findings to Crosby's foundational model.

Mann's new narrative has plenty of twists, and even some instances of inadvertent Native American revenge. He describes how the explorer Francis Drake brought the potato back to England, where it spread to Ireland and Ukraine -- only to betray the peasants who had come to depend on it when it fell prey to diseases for which it had no immunities. (To compound the irony, the culprit was a fungus that came with guano, the excrement that had been stripped from Peruvian islands in order to fertilize European farms.) The exchange came full circle when, following the potato famine of 1845-52, the Irish started moving in droves to the Americas.

Mann also globalizes what was for Crosby an essentially Atlantic exchange. New World resources and crops reached as far as China, establishing a worldwide commercial network. Europeans' access to American silver allowed them to trade for Chinese silks, bringing China back into the international order, from which it had withdrawn in the fifteenth century. China also imported new grains and tubers, which allowed its agrarian frontier to spread and its population to grow. The humble American sweet potato helped China double its population, to 300 million, by 1800.

These developments support Mann's view that globalization started much earlier than most scholars assume. But his figures are not quite as reliable as one might hope. His estimate, for example, that China sucked up half of the New World's silver output does not rest on solid foundations. Mann's 1493 also contains a number of embellished claims, such as his assertion that Mexico City was the first of the world's "modern, globalized megalopolises."

Despite these rhetorical flights, Mann succeeds in demonstrating that after 1492, the world became not just interconnected but interdependent. From the convergence of two old worlds emerged one: ours. But 1493 is no emollient history of globalization. Mann shows how the transfer of biota, knowledge, and assets from Europe to the Americas was a profound, wrenching, and, for Native Americans, pitilessly devastating process. By 1650, 90 percent of the native population had been wiped out. In 1491, Mann recounts how large and sustainable the pre-Columbian population was; in 1493, he details the findings of demographic historians, such as Noble David Cook, who have charted the wave after wave of epidemics that ravaged the survivors of the conquest. Meanwhile, the countries most greedily importing American silver, China and Spain, were soon beset by inflation and economic turmoil. Still, in the end, biology, not technology, gave Europeans the advantage.

NEW WORLD ORDER

The most obvious contribution Mann's books make to the history of globalization is the often forgotten point that the New World was central to the story of global integration. His books will continue to challenge Eurocentric histories, such as Niall Ferguson's recent Civilization: The West and the Rest, in which a half dozen Western "killer apps" do the handiwork of Europe's ineluctable triumph over the rest, including the Americas. Mann reminds those who tend to think of the Americas as having remained essentially separate from the rest of the world until the United States emerged as a superpower that the hemispheres actually had a deep history of interaction. And he forcefully rebuts those, such as Ferguson, who tend to think that Europeans invented modernity on their own. Globalization was not a unique European creation; it could not have been possible without the resources that Native Americans had already figured out how to exploit before 1492.

Mann's second message is that the accumulated learning of the original Americans -- their mastery of nature -- survived the catastrophe of the Columbian exchange. The wardens of that learning are the Native Americans' descendants, who continue to make use of resources in artful and productive ways. Take, for example, Rosario and her family in Brazil. By letting messy shrubbery grow along the tributaries of the Amazon River, they create habitats to harvest shrimp alongside trees for producing limes, coconuts, and hearts of palm. This mishmash does not look like an orderly farm, but it is lucrative and sustainable. Models such as these serve as a rebuke to trendy environmentalists in the West who want to slow or stop the human exploitation of natural resources altogether. And it challenges those industrialists who want to release man and machine from all constraints in a mad rush to exploit today's commodity boom. The clash of these two philosophies takes place almost exclusively in the global North. Most of their counterparts in the South do not think much of either option and reject the false choice between pure predation and deforestation, on the one hand, and untouched wilderness, on the other.

It is no secret that globalization has been a disaster for some and a boon to others. That it has been the cause of great ecological transformations, dating back to Columbus' arrival in the Americas, is less well understood. Any future textbook on world history will have to reckon with this development and its portrayal in Mann's books.

**************

CORRECTION APPENDED (April 26, 2012)

This article has been revised to address an error in the original version, which incorrectly stated that tobacco originated in the Old World.