Written by one of the world's specialists on the species, and based on six years of field study, this monograph covers the last and rarest of the African great apes, the pygmy chimpanzee. Apart from the obvious physical differences with the more familiar `common' chimpanzee, this ape also has markedly different behavioural, social and ecological relationships, and comparisons are drawn between the two species. Pygmy chimpanzees are also thought to be man's closest living relative.