In this controversial, thought-provoking, and brilliant book, renegade thinkers Christopher Ryan and Cacilda Jethá debunk almost everything we "know" about sex, weaving together convergent, frequently overlooked evidence from anthropology, archaeology, primatology, anatomy, and psychosexuality to show how far from human nature monogamy really is. In Sex at Dawn, the authors expose the ancient roots of human sexuality while pointing toward a more optimistic future illuminated by our innate capacities for love, cooperation, and generosity.