This study is an analysis of the roots of human savagery, dealing with the fundamental questions of why the majority of violence is perpetrated by men, whether this is a matter of nature or nurture and whether anything can be done about it. The book provides some surprising answers, based on comparison of male violence among human and among man's closest relatives, the great apes. In three or four species, male violence is common, but the form of violence differs: male organgutangs tend to rape, male chimps wage war and male gorillas kill the offspring of other males. Only in the fourth species, the little-known bonobo, are males (as well as females) non-violent - females are co-dominant, there is no observable aggression between groups, and there is a high level and diversity of sexual activity. The findings are based on 30 years of field research on the behaviour and ecology of chimpanzees and other mammals in Africa.