Sexual selection, or the struggle for mates, was of considerable strategic importance to Darwin s theory of evolution as he first outlined it in the "Origin of Species," and later, in the "Descent of Man," it took on a much wider role. There, Darwin s exhaustive elaboration of sexual selection throughout the animal kingdom was directed to substantiating his view that human racial and sexual differences, not just physical differences but certain mental and moral differences, had evolved primarily through the action of sexual selection. It was the culmination of a lifetime of intellectual effort and commitment. Yet even though he argued its validity with a great array of critics, sexual selection went into abeyance with Darwin s death, not to be revived until late in the twentieth century, and even today it remains a controversial theory. In unfurling the history of sexual selection, Evelleen Richards brings to vivid life Darwin the man, not the myth, and the social and intellectual roots of his theory building."