There are twin myths about American Indian cultures before Columbus: that they were mostly primitive hunter-gatherers, and that they lived lightly on the land in harmony with nature, like some proto-hippies. Mann's book collects most of the currently available information disputing those myths.
The reasons these myths arose are easy to see in retrospect. European diseases wiped out possibly 90% of the population of the New World in the 130 years after 1492. 90%. Think about that. Some estimates actually range as high as 95%; none now drop below 75%. When the Jamestown and Mayflower settlers arrived, there were five to ten million inhabitants of North and South America - little wonder that we came to regard our continent as essentially empty for us to take, with little accommodation for the few natives. At that point, it was. But if the population was more like 100,000,000, as it may have been in the late 15th C, our impression changes.
Smallpox and a hantavirus similar to Hepatitis A did most of the damage in repeated waves. What the Europeans encountered were bare remnants of larger groups. These shattered cultures were not only reduced in number but in spirit: they could no longer sustain the type of economies they were used to, and they believed that the gods themselves and all of nature were against them. Some of the earliest accounts of the colonists reflect this, but these were replaced in the popular imagination by the observations of those who came after. What to the Indians was an adaptation to catastrophic circumstances came to be seen as their normative state, extending backward into centuries of similarity. The Indians believed this about themselves as well, for after a few generations they had no record and little memory of what had been before.
As European settlers moved across America, they encountered groups that had been decimated and were little like what they had been even a hundred years earlier.
Further obscuring the previous reality was the concentration of native population and civilization south of the Rio Grande. The earliest Spanish explorers brought many who recorded what they saw, but after 1600 Spain was already in decline, less curious and preserving less of what they knew of the New World. The English and French kept alive what they knew, but only the Hopewell/Mississippian cultures built cities in what are present-day America and Canada. We only gradually learned about the Aztecs, Mayans, and Incas, long ofter our mental picture of the New World was formed.
As the rejection of capitalism, Christianity, and technology came into full swing after 1960, the Native American approach to life took on a mythic quality. No longer Indians, these disparate tribes entered the American consciousness as idyllic noble savages, cleverly able to use every part of the buffalo for something, living lightly in harmony with nature and respect for life that stupid honkies/gringos/Europeans were unable to appreciate. Well, no. Indians managed and manipulated their environments as much as Europeans and Asians did. They were often amazingly clever, discovering interventions that the Old World would not figure out for centuries, but they were conquerors, rather than harmonizers with nature, just like us. They also occasionally made destructive mistakes that eliminated species and needlessly destroyed habitat, just like us.
None of this was new to me, and I couldn't understand why Mann kept hammering on the point of how misunderestimated the New World was. He eventually proved the point. By enormous wisdom or dumb luck, my one course in Mesoamerican anthropolgy, plus my ongoing fascination with both proto-world linguistics and colonial New England had delivered to my mind a different schema of what the Americas were like than is at all common. I find this amazing, as even my childhood Dennis the Menace Goes to Mexico comic book recorded the importance of smallpox in Cortes' conquering of the Aztecs. Apparently Hank Ketcham's work was not widely read in scholarly circles. But there it is: all of you out there were ignorant fools, and only the Assistant Village Idiot preserved this knowledge.
In fairness, the book provided details and updates that were unfamiliar to me. It is a history of the New World, and there has been a lot of excavation since I left William and Mary. Norte Chico was completely new to me, as were the intriguing new clues about Amazonian cultures. All the nasty infighting among anthropologists, though unsurprising to anyone who has been privy to the childishness of academics in other fields, was also new - and entertaining. Stories of favored former graduate students pointedly ignored at conferences for having the temerity to suggest that Olmecs may have reworked an older god rather than adopting the Staff God directly from the Andes just confirm all our prejudices of the pettiness of intellectuals, don't they?
Mann also collects in one place an enormous amount of the evidence of the repeated tactical mistake Indians made upon the arrival of Europeans. Wampanoags, Aztecs, Comanches, and Incas all attempted to use the newcomers as leverage in their own inter-tribal conflicts. In our current formulation, we see the parties as divided into two groups: Indians and white men. This was not how it appeared to anyone at the time. The Wampanoags saw the English Puritans as allies against the Narragansett and Massachusett tribes. The English thought of themselves as quite separate from the French, Dutch, and Spanish. This has its echo in our understanding of the Crusades. We now see this as a conflict between Muslims and Catholics, but the participants did not see it this way. Various Islamic tribes allied with the Crusaders for advantage against their competitor tribes, and Crusaders often did not understand or respect the difference between Moslems, Copts, Jews, and Orthodox. We impose our current struggles back upon our ancestors.
Now let me tell you what's wrong with this book. I may be the first. All the reviews online gush with how wonderful it is. Once you've dropped the Indians-as-Greenpeace activists meme, the idea that the New World was really older than the Old World, with better cities, better engineers, wiser farmers, and free hallucinogens seems to be the politically correct one. Mann seems determined to explain how Toltecs and Mixtecs were just like Venetians or Egyptians, only earlier and better. It gets tiring, because the evidence he uses often admits of several interpretations. It is reminiscent of HG Wells The Outline of History, in which he solemnly declares, in describing a chieftain of ten thousand years ago "No one was allowed to touch his spear." Oh really? Do tell. Mann makes similar leaps about the religious festivals and machinations of government of civilizations which leave no written record. He retains some caution and humility, sprinkling "might," "may have," and "perhaps" throughout these descriptions, but it's not far from The Motel of the Mysteries in some places.
By the time he gets around to quoting Ward Churchill - yes, that Ward Churchill - about how the Europeans should have known that their diseases were wiping out Indians and done...well, something, I was already annoyed at the inability to reverse situations or compare them to anything else in known history. You are English in 1594 and it you have heard that the natives in Canada seem to be dying off from diseases brought by the French, and you are supposed to do what exactly? And when you figure that out, do you go back and blame the modern Chinese for the Black Death, or is this something that only applies to evil Europeans?
In similar fashion, do we credit the yearly burning of most of the undergrowth of the Eastern forests and all the Great Plains for the global warming that brought us out of the Little Ice Age, or do we give the Indians a pass on that, or credit, or what?