A retrospective biography on Muhammad Ali, who grew up in Louisville, Kentucky, as Cassius Clay Jr., and by 1963 had won 18 boxing matches and built a reputation as the "Louisville Lip" with his trademark self-assurance. He became the heavyweight champion of the world in 1964 and also changed his name to Muhammad Ali that year; he was a conscientious objector to the Vietnam War; and by the end of the 1970s, he was the most famous boxer of all time; in 1983, he was diagnosed with Parkinson's disease and continued his fighting spirit working endlessly for various humanitarian causes until his death.