Another bio of the flamboyant astronomer and creator of Cosmos (see William Poundstone, p. 1391), from a veteran science writer (coauthor with George Smoot of Wrinkles in Time, 1993). Davidson credits Sagan’s influential Intelligent Life in the Universe, a collaboration with Russian astronomer I.S. Shklovskii, with awakening his own interest in science. He recognizes Sagan as a great popularizer, one of the preeminent translators of scientific ideas into the vernacular of his day. At the same time, he clearly distrusts the myth that Sagan often seemed to personify, that of the scientist as a sort of modern high priest, omniscient and above the fray. In this spirit, the biography often seems to be recounting Sagan’s career with an eye to undercutting that myth, if not necessarily the man himself. Thus the digs at Big Science, where political acumen counts for as much as research ability; the quotation of derogatory remarks from Sagan’s former friends (e.g., Harold Blum, who called his prose style “phony”); and hints that there were deep-seated irrational elements behind the cool surface of Sagan’s science. Sagan was clearly a man who made enemies as easily as friends, and Davidson has sought out both camps. The resulting portrait is not so much a debunking of Sagan, however, as a highlighting of certain qualities that might have increased his popular appeal. The “nuclear winter” episode, in which Sagan and several colleagues argued that even a “limited” nuclear war might lead to the extermination of human life, showed Sagan as an eminent scientific expert, paradoxically arguing that the issues involved were too important to leave to the experts. Likewise, in many ways Sagan’s constant advocacy of the search for life beyond Earth—the central science-fictional dream—was a key to the space program’s becoming hard reality. In the end, Davidson argues, Sagan’s influence in such matters may count for more than any of his books. A smoothly written, sometimes critical look at a leading scientific figure of our time.