1491: New Revelations of the Americas Before Columbus

Mann first treats New England in the 17th century. He disagrees with the popular idea that European technologies were superior to those of Native Americans, using guns as a specific example. The Native Americans considered them little more than "noisemakers", and concluded they were more difficult to aim than arrows. Noted colonist John Smith of the southern Jamestown colony noted that "the awful truth ... it [a gun] could not shoot as far as an arrow could fly". Moccasins were more comfortable and sturdy than the boots Europeans wore, and were preferred by most during that era because their padding offered a more silent approach to warfare; canoes could be paddled faster and were more maneuverable than any small European boats.

Mann explores the fall of the Inca Empire and attempts to assess their population compared to the armies of conquistadors, such as Francisco Pizarro. He discusses the importance of the large number of newly introduced infectious diseases and the likelihood that these played a far more significant role in the Native American decline than warfare or other actions by Europeans. He notes that while Europeans probably derived less benefit from their possession of horses than expected, as e.g. the stepped roads of Inca settlements were impassable to horses, the Inca did not maximize their use of anti-horse inventions to stop the Spanish intruders. The Inca Empire collapsed because by the time Europeans arrived, smallpox and other epidemics had already swept through cities, due mostly to the natives' lack of immunity to Eurasian diseases.

The contrasting approaches of "High Counters" and "Low Counters" among historians are discussed. Among the former, anthropologist Henry F. Dobyns estimated the number of pre-Columbian Native Americans as close to 100 million, while critics of the High Counters include David Henige, who wrote Numbers from Nowhere (1998).

Mann then goes into the provenance and dating of human remains that may shed light on the period of first settlement of the Americas. The Clovis culture in New Mexico was one of the first to be assessed using carbon dating. While it at first appeared to originate between 13,500 and 12,900 years ago, following immigration from Siberia over the Bering land bridge, recent evidence indicates that Paleo-Indians were present in the Americas at even earlier dates.

Agriculture is another focus of this section, as Mann explores Andean and Mesoamerican cultures. The agricultural development of maize from essentially inedible precursors like teosinte was significant for the rise in crop surpluses, populations and complex cultures, and pivotal in the rise of civilizations such as the Olmec. Mann notes that Mesoamericans did not have the luxury of "stealing" inventions from others, since they were geographically isolated in comparison to the cultures of Eurasia, leading to an absence of inventions that played fundamental roles in other cultures (such as the wheel) and also lacked domesticated large animals.

In the third section, Mann attempts a synthesis. He focuses on the Maya, whose population growth appears to have been as rapid as its decline. The canonical theory about the disappearance of Mayan civilization, a pattern common among many Native American cultures, was stated by Sylvanus Morley as:

"the Maya collapsed because they overshot the carrying capacity of their environment. They exhausted their resource base, began to die of starvation and thirst, and fled their cities 'en masse', leaving them as silent warnings of the perils of ecological hubris."

Mann discusses the growing evidence against the perception that Native Americans were not active in transforming their lands. Most Native Americans shaped their environment with fire, employing slash-and-burn techniques to create grasslands for cultivation and to encourage the abundance of game animals. Native Americans domesticated fewer animals and cultivated plant life differently from their European counterparts, but did so quite intensively. The author suggests that limited and often racist views about the indigenous people, in addition to lack of a common language among the indigenous people, often led to a failure to recognize these dynamics, and has historically found expression in conclusions like the "law of environmental limitation of culture" (Betty J. Meggers) — whatever Native Americans did before slash and burn, the logic goes, had to have worked thanks to the vast expanses of healthy forest seen before Europeans arrived.

Mann argues that Native Americans were a keystone species, one that "affects the survival and abundance of many other species". By the time the Europeans arrived in number to supplant the indigenous population in the Americas, the previous dominant people had been almost completely eliminated, mostly by disease, with a consequent disruption of societies and environmental control. Decreased environmental influence and resource competition would have led to population explosions in species such as the American bison and the passenger pigeon, and because fire clearing had ceased, forests would have expanded and become denser. The world discovered by Christopher Columbus was to begin to change from that point on, so Columbus "was also one of the last to see it in pure form".

Mann concludes that we must look to the past to write the future. "Native Americans ran the continent as they saw fit. Modern nations must do the same. If they want to return as much of the landscape as possible to its state in 1491, they will have to create the world’s largest gardens."

• Michael Coe, "The Old New World", American Scientist, July–August 2006 issue.
• Mary D'Ambrosio, "The myth of an empty frontier: Explorers' diseases wiped out native populations long before settlers arrived", San Francisco Chronicle, August 14, 2005.
• Alan Taylor, "A Cultivated World", The Washington Post, August 7, 2005; BW05
• Bruce Ramsey, ""1491": Discovering what Americas were like before Columbus", The Seattle Times, August 12, 2005