In the late 1970's, more than 15 years after Jane Goodall set out to study the chimpanzees of Tanzania's Combe forest, Ghiglieri took on the yet unstudied chimps of the Ngogo forest reservation in Ughanda--a region the ancients had placed ""beyond the mountains of the moon."" Comparing his chimps with Goodall's, Ghiglieri found some behavior differences that he believes are ""cultural."" There are also considerable differences between the observers: Whereas the unschooled Goodall was tapped for her mission by Louis Leakey because, in her words, ""he wanted someone with a mind uncluttered and unbiased by theory,"" Ghiglieri casts his observations within a framework of sociobiological analysis. And where Goodall initially lured the Gombe chimps with supplies of bananas, Ghiglieri gained access to his subjects by hanging out at the flourishing fig trees where they feed. His goal, in its narrowest definition, was to explain the apparent systematic murder of ""outside"" males that Goodall observed after she discontinued her banana handouts. Was the territorial killing a natural behavior pattern or was it an anomalous response to Goodall's manipulation of their ecology? Though Ghiglieri himself never witnessed such killings, he concludes that the sexual behavior of both male mad female chimps supports the hypothesis that their society is based on lethal territorial aggression by kin-related males. His argument draws from his own and others' observations and for Ghiglieri, whatever the behavior, ""the explanation is genetic, or, in other words, sociobiological."" And he makes a persuasive case for it. Though Ghiglieri names his subjects in the established ape-watchers' tradition, and maintains that he developed attachments and relationships with individual chimps, he doesn't bring the chimps or the experience to life as do Goodall and Dian Fossey in their more engaging and involved reports on primate communities. However, his more sophisticated second-generation study makes good use of earlier findings in applying a neo-Darwinian perspective to the creatures that geneticists have found our closest living relatives.