There are a number of books out there devoted to various versions of the "paleo lifestyle", each with their own vision of the best way to live "the way things were". However, today I want to bring to your attention a book that doesn't even try to tell you how to eat - at least, not directly. "Good Calories, Bad Calories" was written by Gary Taubes, and published by Anchor Books, initially in 2007 (and softcover in 2008).
Gary Taubes is not a doctor, a nutritionist, a paleo-anthropologist, or anything like that. He's a science journalist. He makes a living writing about the research that other people do, and his articles have appeared in the New York Times Magazine, among other publications. In fact, that's where the inspiration for this book came from - through an article he wrote for the NYTM called "What If It's All Been A Big Fat Lie?", which questioned the value of low-fat diets for weight loss.
Following on from the research for that article, Gary interviewed hundreds of people and read hundreds of scientific papers. The bibliography of my (softcover) edition of the book is 66 pages in length. In other words, this book draws on an awful lot of material, and he tells you where to check if you don't believe him.
There isn't nearly enough room in this blog to tell everything he covers in the book (and that would be plagiarism besides), but the evidence he lays out is pretty damning of the state of "nutritional guidelines" today, and a solid foundation for the paleo lifestyle. Chiefly, there is a lot of evidence he covers that strongly indicates that dietary fats (as long as they're the right kind of fats - as a hint, vegetable oils are not your friends) are not all that bad for us, and refined carbohydrates are, in fact, public enemy number one (dietarily speaking, anyway).
Curiously, (and this is my chief complaint about the book) Gary never actually goes "the last mile" and draws any hard conclusions - he's obviously leaving that up to the reader. However, if you read this book (and everybody should), you will come away with a feeling that the Western diet is "doing it wrong".
This book will tell you what's wrong with diets today. If you want to understand a lot of the science behind the paleo diet, this would be a very good first step.
As a bonus, here is a link to a copy of the Letter On Corpulence, written by William Banting in 1863 - a hundred years before Doctor Atkins and his "New Diet Revolution" (hosted on the Atkins website, no less).