AThink of the word "evolution" the name Darwin and the term "natural selection" come to mind. But any powerful general theory of evolution must account for social evolution, both human and nonhuman, and contemporary Darwinism has not persuasively made such an accounting. In Interactions: The Biological Context of Social Systems, Niles Eldredge and Marjorie Grene argue effectively and coherently against the reductionist tendencies in modern...