1491 is part science text, part history book. Charles C. Mann's main premise is that the Americas in 1491 were a much different place than our history books say they were.

Mann's first line of attack is the "empty America" syndrome. He claims there were as many people living in North America as there were in Europe, prior to decimation by smallpox and other European diseases. In the process he also belittles the "pristine America" argument. Prior to the smallpox pandemic, Indians burned the underbrush of our forests; the result was more of a parkland than a wild Garden of Eden. The forest stretching from the coast to the Mississippi came afterward, when the Indian caretakers had been depleted.

Most impressive for me was Mann's analysis of Indian technology. For instance, maize was not an indigenous plant. It was genetically engineered from a mountain grass called teosinte. The Amazonian Indians of South America also managed to invent their own soil, "terra preta," a sort of mixture of pottery shards and charcoal. The South American Indians even experimented in social engineering. Inca warriors would infiltrate villages, "convince" their rulers that accepting Inca rule would be beneficial to their people, then gradually take over. Once in control, they would move some of the subjugated population to others villages where they were required to learn the Inca language. The Incas even managed to "eradicate hunger" in an empire larger than that conquered by Alexander the Great.

Mann hopscotches back and forth between such diverse cultures as Triple Alliance (Aztecs) in Central America to the Haudenosaunee (Iroquois) in Canada and New England. Each has a surprise in store for the reader. For instance, it's not true that the Aztecs never invented the wheel. Children's toys have been unearthed with definite wheels. Mann theorizes that because of the mountainous and wet environment the Aztecs scorned the invention. Then he compares them to Europe, where our supposedly superior civilization never did invent the plow; it had to be imported from China.

Another criticism of Native American culture is that they had no system of writing. Mann counters this misconception with the Inca's "khipu," sort of three-dimensional stringed knots, which were felt and read. Scientists are still trying to decipher them. Mixtec Indians also left behind "codices," deerskin or bark books whose painted pages looked rather like murals.

Native America civilizations also appear to be much older than the history books say. The Clovis culture, for instance, has been carbon-dated to between 13,500 and 12,900 years ago and archaeologist Alex D. Krieger lists fifty sites said to be older yet. Some scientists maintain that paleo-Indians "walked or paddled" to Peru fifteen thousand years ago.