When Strum first set out in 1972 from California to do graduate work with baboons in Kenya, conventional wisdom had it that primate society, epitomized by monkeys such as baboons, was ruled by aggression, and that the large adult males dominated one another and their group by brute force. But her fascinating chronicle of 15 years spent observing a troop of baboons nicknamed the Pumphouse Gang has revealed startling new aspects of animal behaviour...