"I had never planned to become a savanna baboon when I grew up; instead, I had always assumed I would become a mountain gorilla," writes Robert Sapolsky in this witty and riveting chronicle of a scientist's coming-of-age in remote Africa. A professor of biology and neurology at Stanford, he interweaves serious scientific observations with wry commentary about life in the Serengeti -- for man and beast alike -- in this exhilarating account of his 21-year study of a troop of rambunctious baboons in Kenya.  (EAF368, $16.00)