In Unto Others, philosopher Elliott Sober and biologist David Sloan Wilson bravely attempt to reconcile altruism, both evolutionary and psychological, with the scientific discoveries that seem to portray nature as red in tooth and claw. The first half of the book deals with the evolutionary objection to altruism. For altruistic behavior to be produced by natural selection, it must be possible for natural selection to act on groups--but conventional wisdom holds that group selection was conclusively debunked by George Williams in Adaptation and Natural Selection. Sober and Wilson nevertheless defend group selection, instructively reviewing the arguments against it and citing important work that relies on it. They then discuss group selection in human evolution, testing their conclusions against the anthropological literature. 　　In the second half of the book, the question is whether any desires are truly altruistic. Sober and Wilson painstakingly examine psychological evidence and philosophical arguments for the existence of altruism, ultimately concluding that neither psychology nor philosophy is likely to decide the question. Fortunately, evolutionary biology comes to the rescue. Sober and Wilson speculate that creatures with truly altruistic desires are reproductively fitter than creatures without--altruists, in short, make better parents than do egoists.