Since any mention of a particular group selection theorist seems to elicit a lot of comment on this blog-I think it would be good if people read the more central figures behind the modern day revival of this idea. RE-INTRODUCING GROUP SELECTION TO THE HUMAN BEHAVIORAL SCIENCES is a short article by David Sloan Wilson & Elliott Sober expostulating their core ideas. Unto Others: The Evolution and Psychology of Unselfish Behavior is a full book length treatment.