Sex at Dawn

Christopher Ryan and Cacilda Jethá take aim at the standard account, dating back to Darwin, that sexual monogamy comes naturally to humans. Their central claim is that early humans lived in egalitarian hunter-gatherer bands where food, child care and often sexual partners were shared, and that paternity was of little concern before agriculture brought dense populations. Drawing on anthropology, primatology, archaeology and anatomy, they cite testicle size, hidden ovulation and the appetite for sexual novelty, compare early human mating to that of bonobos, and argue that many researchers project modern assumptions onto prehistory. They also ask why fidelity can be so hard and passion tends to fade. Press reviews were generally positive, while many scholars criticized its method and conclusions.

Sumo founder Noah Kagan included it in his list of 18 books that changed his life.