A review of this — 5 years ago
Dawkins has thought a lot about genes and their effect on the behavior of organisms. This book gives counter intuitive explanations on why organisms (including humans) are the way they are. Very complex sets of behaviors are broken down into clear and simple explanations of replicators and natural selection.
The only reason I do not give the book 5 starts, is that Dawkins tends to digress from his main point too far and too often.