On October 30, 1974, in Kinshasa, Zaire, at the virtual center of Africa, two boxers were paid five million dollars apiece to confront each other in an epic match. One was Muhammad Ali, who vowed to reclaim the championship he had lost. The other was George Foreman, who was as taciturn as Ali was voluble and who kept his hands in his pockets "the way a hunter lays his rifle back into its velvet case." Observing them both was Norman Mailer, whose...