Robert Wright is an exponent of the "evolutionary psychology" movement - that is, the notion that our civilization and its institutions, manners, laws, customs and religions are all a part of the evolutionary process. We are the sum of our genes but we are much more than that - the moral animal. We worry about what others think about us, about what we do, about right and wrong and evil and love and good and bad.
Wilson has made similar arguments in his excellent works and this book is a supporting cast member in the long drama of evolutionary science. The book is not technical but it is extremely interesting - discussing such concepts as male, female, sex, family, groups, altruism - all with a focused eye and calm, measured vocabulary. He looks at our reasons for doing what we do, why we like certain people and more importantly, why we dislike others and live life as we do.
One problem common to many books of this type is the almost worshipful homage to Darwin. His thoughts on many subjects are treated as Scripture at times and his life is studied for what he offers in other realms besides natural selection. While Darwin may have brought about a synthesis of scientific thought at the time, it is fair to say that technically he was surpassed long ago. In the end, this is a book about the qualities that make us human and different than other animals on Earth.