Give yourself a pat on the back. You're not as stupid as everyone says you are, and now there's a book that proves it.

When I first conceived of The Logic of Life, my aim was to show that a world full of smart people--people like you, that is--doesn t necessarily look logical on the surface. We eat too much and worry about being fat; drink too much and cringe when we remember; spend too much at Christmas and worry about the bills in New Year. And that s just the small stuff: what about crime, racial segregation, divorce, big-money politics?

And yet underneath it all there is a hidden logic. It isn t always pretty, but it s there if you know how to see it. That is what The Logic of Life is all about.

But when I'd finished the first draft, my editor told me that he didn't think that people were as logical as I'd said. He wanted me to prove my point.

At first, I thought it was my editor thinks people are illogical because he works in the publishing business. Of course life looks illogical if you do that. (In fact, life looks crazy in most offices: see "Why Your Boss is Overpaid," chapter four.) But then I realised he was right. I'd left the most important step out.

So I went back and made sure that I laid out all the amazing evidence. I looked at single women hitting the dating scene in American cities; I looked at juvenile delinquents across the US; I looked at Mexican prostitutes; I looked at traders at a convention in Disney World; I looked at professional poker players in Las Vegas and professional soccer players in Europe. I looked at violent spouses, alcoholics, and school bullies.

In every case I discovered a story of hidden incentives and unexpected logic. And through the process of writing--and living--the book, I discovered that this crazy world of ours makes more sense than you might think.