Daniel Ellsberg achieved fame in 1971, at age 40, when he leaked a massive, top-secret Pentagon study about U.S. involvement in the Vietnam War to the New York Times, helping to spur the Watergate scandal. Ellsberg's act of conscience, leavened as it apparently was by vainglory, deserves study. But his obscure if interesting life hardly merits a massive biography. Wells (The War Within: America's Battle Over Vietnam), a sometime college professor, has researched Ellsberg in all his guises: the not-very-nice-guy, the public-policy whiz kid, the macho soldier, the Vietnam War hawk-turned-dove, the nearly-convicted-traitor-to-his-country, the elder sociopolitical activist. Wells also researched Ellsberg's milieus—the elite private school in suburban Detroit, Harvard University, the RAND Corporation think tank in northern California, the Pentagon, the Marine Corps, Vietnam's battlefields. Ellsberg cooperated initially, but bridled at negative assessments of his character passed along by Wells during interviews and at Wells's suggestion that Ellsberg was self-aggrandizing. Eventually, Ellsberg stopped cooperating, although his compulsion to talk about himself yielded unexpected chats. Despite insightful passages about peace and war, altruism and vanity and other polarities, this bloated book could have been a lengthy magazine article. Beyond the Pentagon papers, Ellsberg's life comes off as fairly inconsequential, and his evident mania for sexual conquest, including that of two women who married him and bore him children, gets boring after the first few dozen instances. (June)