This innovative book challenges the perceived view, based largely on long observation of artificially-fed chimpanzees in Gombe and Mahale National Parks, Tanzania, of the typical social behaviour of chimpanzees as aggressive, dominance seeking, and fiercely territorial. In polar opposition, all reports from naturalistic (non-feeding) field studies are of non-aggressive chimpanzees living peacefully in non-hierarchical groups, on home ranges open to all. These reports have been ignored and downgraded by most of the scientific community. By utilizing the data from these studies the author is able to construct a model of an egalitarian form of social organization, based on a fluid role relationship of mutual dependence between many charismatic chimpanzees of both sexes and other more dependent members. This highly and necessarily positive mutual dependence system is characteristic of both (undisturbed) chimpanzees and (undisturbed) humans who live by the 'immediate-return' foraging system.