A superb update of the 1977 bestseller Origins, in which famed anthropologist Leakey (One Life, 1984, etc.), assisted by veteran science-writer Lewin (Bones of Contention, 1987), pondered the mysteries of human nature. Leakey is the ""I"" in this first-person account, which includes not only scientific speculation about prehistoric human origins and development, but also a flurry of anecdotes from his personal adventures in the field over several decades. Autobiography and analysis both pivot on the discovery in 1984 by Leakey and his associates of ""the Turkana boy,"" a 1.5 million-year-old Homo erectus fossil. The ""eureka!"" of the find is palpable (""Could we really be on to a skeleton?...We hardly dared voice the speculation--the hope--out loud""), as is Leakey's awe. He details the Turkana boy's daily life, and contrasts Homo erectus culture to that of other early hominids. This leads to conjectures on other puzzles of prehistory: How did consciousness arise? Language? Art? Why did Neanderthals disappear? At times, the answers come by means of new paleontological tools like molecular biology and dental-growth analysis, and Leakey's explanations of these high-tech procedures--usually while detailing a pitched scientific battle between opposing researchers--are models of lucidity. Fans of scientific squabbling will also enjoy watching him keep the heat on archrival Don Johanson, discoverer of ""Lucy,"" challenging him on everything from fossil classification to the derivation of the hominid line. Less enticing, perhaps, is Leakey's philosophical materialism, in which the sole reason for human intelligence is our ""need to understand and outwit others in the drive for reproductive success."" A few years ago, Leakey turned in his paleontological pickaxe; he now works full-time--surrounded by a retinue of bodyguards--as director of Kenya's antipoaching Wildlife Service. This may be his swan song as a fossil hunter. If so, it's a tingling farewell; if not, it's still vintage Leakey.