Just over 20 years ago the publication of two books indicated the reemergence of Darwinian ideas on the public stage. E. O. Wilson's Sociobiology: The New Synthesis and Richard Dawkins' The Selfish Gene, spelt out and developed the implications of ideas that had been quietly revolutionizing biology for some time. Most controversial of all, needless to say, was the suggestion that such ideas had implications for human behavior in general and social...