There never ceases to be interest in the ways of birds and bees, nor new generations of writers to wax eloquent about them. Walters, a science writer and editor at Reader's Digest, is one such enthusiast--not as polemical as the macho sociobiologlsts of yore, but willing to quote them as well as the new wave of animal-watchers in the shadow of lane Goodall. Walters speculates that sex may have had its origin in earlier cellular comminglings he calls cannibalism but which may have arisen as fortuitous symbioses. He proceeds through the animal kingdom from marine organisms like horseshoe crabs and grunions--the latter timing their fertility rites to peak high tides on California beaches--to pygmy chimpanzees (maybe our closest relatives) observed in the wild and in primate centers like Yerkes in Georgia. Courtship displays, appeasement/aggressive behaviors, dances, calls, mimicry, pheromones, nesting behavior--the whole panoply of pre-sex/intercourse and sequels are sketched for many species, with special emphasis on birds. Indeed, one the most memorable sections describes the heroic attempts to preserve whooping cranes. The problem was that Tex, the female in captivity, had been imprinted on her human handler. So, at each mating season, he dutifully danced with her, learned her calls, and at the magic moment, enlisted confederates to inseminate her. After several unsuccessful seasons an egg did survive--but mother herself succumbed to the savagery of raccoons only weeks later. The urge to anthropomorphize is ever near, and although Walters is quick to add caveats, he is not above discussing animal rape, infidelity, polygamy, and incest. While much of this is familiar and raises familiar questions about the logicality of animal behavior and its relevance to humankind, there is some intriguing new information--about the rampant, nearly omnipresent sex-play of pygmy chimpanzees, for example, in sum, some things old, some things new, generally well told.