Mailer subtly exercises his novelist's imagination and expends considerable journalistic shoe-leather probing our central cultural conundrum -- Lee Harvey Oswald: Patsy or Lone Assassin? He starts in Minsk, where Oswald spent two and a half years after getting out of the Marines in 1959. Having interviewed what seems like half the population of that small Soviet city, Mailer gives us an Oswald slightly disaffected, by no means friendless, adept at jerking bureaucracy's chain. He takes a wife, they fight often. (The author's voice does not intervene in Minsk; later, Mailer interpolates sections of interpretation as to what happened and why.) Then the Marines: Oswald as overgrown playground butt, possibly passing some low-level secrets to somebody. On to Dallas. The Oswalds are looked upon as charity cases by the Russian emigre community. Oswald, frustrated, reads Mein Kampf and tries to assassinate right-wing general Edwin Walker. He fails. Slowly Mailer enters his subject's spiritual world, seeking the answer (obvious but impressively textured) of why Oswald -- mama's boy, animal lover, wife-beater, half-assed autodidact, ideologue -- might make an attempt on the president's life. Despite the lower middle class grisaille of his existence, Oswald was convinced, like Hitler, that he was destined for greatness. Hitler used his survival in the trenches of WW I as a Sign. Oswald decided that regicide would anoint him. Yet troublesome figures encircle him, including the superbly louche George de Mohrenschildt, with his connections to the CIA, and David Ferrie, the farcically hairless pedophile who was mobster Carlos Marcello's pilot. Mailer's careful and believable verdict: The odds are three out of four that Oswald was a lone gunman. Combining the tedious and the sublime in quintessential Mailer fashion, the text reconstructs Oswald the cipher and pawn, replacing him with Oswald the ideological aspirant with an almost occult belief in his destiny. Judicious, painstaking, and imaginative, this should be a central book in a growing and undependable canon.