Primeval women s swollen breasts indicated lactation, pregnancy and fertility to excited males. In the author s scenario, women lost their estrus and developed permanently enlarged breasts, "an anatomy of deception," to tame and domesticate exploitative males whose interests were narrowly focused only on mating. Female orgasm, though not necessary for reproduction, may have conferred a survival advantage on prehistoric females, the authors further argue. In like fashion, Margulis and Sagan, coauthors of Microcosmos , use evolutionary biology to illuminate orgasm inequality, phallic worship, sexy clothing, sexual jealousy and violence alleged to be rooted in our far-distant past. This eloquent, stimulating exploration of the roots of human sexuality at times succumbs to reductionism, as when the authors ascribe human dating, honeymooning and marriage to the need to maximize reproduction.