In this remarkable work, anthropologist Françoise Héritier charts the incest prohibition throughout history, from the strict decrees of Leviticus to modern civil codes. Through close and subtle readings, Héritier exposes the frequent, but often overlooked, elaborations concerning what she calls a secondary type of incest, namely, the prohibition of two close blood relatives engaging in sexual intercourse with a third person. Héritier not only understands this phenomenon to be as universal as the more classical "first" type of incest banning sexual relations between certain blood relatives, she advances the controversial thesis that the first type may indeed be an outgrowth of the secondary type of incest, once it is understood properly as the transfer of bodily fluids in a love triangle of sexual partners, two of whom are related to each other. Héritier pursues this analysis with erudition and brilliance, through the classical ethnographies as well as the classical civilizations and religions of Rome, Greece, Asia Minor, and Islam. Drawing on her own fieldwork in West African societies where the bans against two sisters are particularly stringent, Héritier fashions a complex "mechanics of fluids" in which blood, milk, and semen form the basis for kinship and prohibition. Her theories, based on the identity and opposition of fluids and essences, expose the connections between the social, the natural, and the bodily, shedding new light on the complexities of kinship theory.