Muhammad Ali called Oct. 26, 1970, his “day of judgment.” His refusal to be inducted to the Army during the Vietnam War, on moral and religious grounds, had pushed him out of the ring for 43 months. But that night in Atlanta, his boxing license restored, he faced “The Great White Hope” Jerry Quarry in his long-awaited return to the ring. Black royalty from Harlem to Birmingham showed up and showed out: Diana Ross, Sidney Poitier, Hank Aaron, and Corretta Scott King filled ringside seats. Filling the stands right alongside them were a bevy of gangsters,...