Hanby and Bygott, a husband-and-wife team, spent four years observing lions at the Serengeti Research Institute; the narrative-report thereon follows the female pride of the Sametu plain, focusing on one of the sisters and working in representative episodes that reveal the lions' social structure, mating and cub-rearing behavior, hunting and territoriality, along with their responses to what Hanby describes as the ""striking seasonal changes in the food supply."" We meet Sonara and her eight sisters as a ""maiden"" pride. Soon they will mate with five visiting males, in a several-day session of incessant copulation that is needed, we're told, to form the bonds of a complex social organization. In time eight of the sisters bear litters--a total of 18 cubs; only three of the cubs will live through their first dry season, though all the adults, resident females and their attendant males, will survive. During the four-year period cubs and males will come and go, the surviving cubs becoming nomads or, if female, remaining with the pride to reproduce. The female core remains as prides regroup and former mates invade their territory. The litters born together share mothers, suckling communally. One mother on an off-schedule bears a solitary litter and must stay behind when the others travel; still, the litter is eventually lost. The scenes of hunting, feeding, and other behavior are the more interesting for the sense that they are particular episodes, not just representative composites; in one, for example, we witness a remarkably tolerant Sonata, impeded in a crucial dry-season hunt by the cubs who insist on clinging to her nipples. In another, a young female tries the difficult life of a lone scavenger but returns chastened to the pride. These observations supplement the picture first projected by George Schaller, founder of the Serengeti lion project, and complement his ground-breaking report with their personal continuity.