I've just been reading Charles Mann's highly readable synthesis of recent work on pre-Columbian America, 1491, and went to recommend it to a friend of mine and gave him a link to Amazon's page about it. Several reviews, unsurprisingly, characterize him as part of the left-wing PC cabal out to demonize Europeans because he characterizes them as physically stunted, smelly, and pock-marked in comparison with the cleaner and healthier Native Americans they met. (The Native-Americans of that era, according to most historians I've read, did have better diets and longer lifespans, and an all around higher standard of living than most Europeans).
However, after perusing the standard right wing assault of left-wing academia, I found that Charles Mann(who has a great web-page) had started a discussion with readers that goes on for about 30+ posts. It's definitely worth reading, especially if you're a teacher of American history, as are a few of the people writing in for tips. One of the things you may notice from the discussion is the good reception that this book has received from a fairly diverse group of readers. Nowhere in the book does Mann claim to be an innovator himself...what he does is bring together a large amount of scholarly research on pre-Columbian America from the 1960s to now and explain its meaning for the general reader. This is probably why he's received praise from the general review press and academics; he treats the academic work with respect and tells you where to find it if you want to go into greater depth and complexity.
You can get to his dialogue with readers by going here.