Much of the evolutionary biology that has grabbed headlines in recent years has sprung from the efforts of sociobiologists and evolutionary psychologists to explain sexual features and behavior--even differences between how men and women think--as evolutionary adaptations. They have looked to the forces of natural selection to explain everything from the mimicry of male mockingbirds to female orgasms among humans. In this controversial book, Richard Francis argues that the utility of this approach is greatly exaggerated. He proposes instead a powerful alternative rooted in the latest findings in evolutionary biology as well as research on the workings of our brains, genes, and hormones. Exploring various sexual phenomena, Francis exposes fundamental defects in sociobiology and evolutionary psychology, which he traces to their misguided emphasis on "why" questions at the expense of "how" questions. Francis contends that this preoccupation with "why" questions (such as, "Why won't men ask for directions"?) results in a paranoiac mindset and distorted evolutionary explanations. His alternative framework entails a broader conception of what constitutes an evolutionary explanation, one in which both evolutionary history, as embodied in the tree of life, and developmental processes are brought to the foreground. This alternative framework is also better grounded in basic biology. Deeply learned, consistently persuasive, and always engaging, this book is a welcome antidote to simplistic sociobiological exegeses of animal and human behavior.