Robert Wright is the author of "The Moral Animal", which is a great book on the topic of evolutionary psychology I've very much
enjoyed to read a few years ago. As a result, I had quite high expectations from "Nonzero". It's probably because of these expectations that I was disappointed by the book. It's not a bad book, but it just isn't what I expected.
As far as I understand, what Wright tries to do is to lay out a unified theory linking cultural and biological evolution together, using game theory. Nonzero is his buzzword for non-zero games "played" by biological and cultural entities (such as the commonly (ab)used Prisoner's Dilemma). The first part of the book deals with cultural evolution, examining historical societies on various stages of development (from hunter gatherers to modern times). The author demonstrates how non-zero-sum-game thinking can explain the behavior of these societies, both internal and external.
Next, the book tackles biological evolution. Here again, Wright uses the nonzero theory to explain how organisms interact, and even how genes inside organisms can interact.
I guess I've found this book disappointing because there was nothing new in it. The first (historical) part is much better covered by other authors, like Jared Diamond. There's nothing particularly innovative in the application of game theory to understand the dynamics of societies throughout history. The second (biological) part is just a much smaller-scale (and worse, IMHO) retelling of some chapters from "The Moral Animal".
So if you've never read any book on such topics before, "Nonzero" can be a good choice - it's written quite well and has enough information to make you think. But if you've read other books on the subject, or plan to do a wider reading overall, I think it's safe to stay away. Read "Guns, Germs and Steel" and "The Moral Animal" instead - it will take thrice as long, but the gain of information and insight is going to be at least tenfold.
Eli Bendersky's website