After years of reading references to this book, I finally got around to reading the book itself. It's now clear to me just why there are so many references out there to it. There are some very interesting ideas, presented in a very coherent fashion.

The thesis is that evolution happens on the scale of "replicators" (genes, usually), not on the scale of individuals or groups. This explains the evolution of altruistic behaviors: a gene can sacrifice the good of the individual carrying it if there's enough benefit to others who are likely to be carrying it as well.

There's a chapter at the end about how genes may no longer be the state of the art in replicators, and that ideas (Dawkins coined the word "meme") may be the next big thing.