Muhammad Ali was the greatest showman, the greatest self-promoter and the greatest humanitarian in boxing history. However, much as it pains me to say this about one of my boyhood heroes, he wasn't the greatest heavyweight of the 20th century, as he was named by a five-member panel assembled by the Associated Press. The Ali of 1965-67—when he was floating like a butterfly and stinging like a bee and making boxing look like the sweet science it assuredly is not—would have been a match for any fighter of any era. Three years does not a career make, and after being forced to take 3� years off to fight his legal battles against induction into the Army, Ali returned in 1970 a different fighter. He was heavier, not as quick and more hittable. Ali never had classic defensive technique: He held his hands low and relied on his speed to make fighters miss. Once he lost a bit of that quickness, they missed less often. An unheralded Ken Norton broke Ali's jaw. Joe Frazier inflicted terrible punishment in their three bouts. Indeed, Ali's best attribute later in his career, sadly, was that he could take a punch.
Yet he rope-a-doped sportswriters with his charm. Even in his prime Ali lacked heavyweight power, which is why a swarming, fearless fighter like Frazier (who was knocked out twice by George Foreman) gave him so much trouble. Of Ali's 27 wins between 1970 and 1978, only 14 were by knockout, an astonishingly low percentage for a heavyweight champion. Journeyman fighters like Joe Bugner, Alfredo Evangelista and Jimmy Young went 15 rounds with him, and Norton and Leon Spinks beat him. Unlike Joe Louis, who for 12 straight years owned the undisputed world title and was the century's greatest heavyweight, Ali achieved only fleeting greatness.
Rocky Marciano was the only heavyweight champion to retire undefeated (49-0-0 with 43 knockouts). He was a savage puncher with either hand and was superbly conditioned every time he stepped into the ring. Marciano (below, right) would trade punches with anyone and knocked out 88% of his opponents, on a par with Mike Tyson (88%) and better than Sonny Liston (78%), and much better than Ali (66%). He was one of only three fighters to beat Joe Louis (in Louis's last fight) and one of only two (with Max Schmeling) to knock out Louis. "The Rock didn't know too much about the boxing book," Louis said, "but it wasn't a book he hit me with. It was a whole library of bone-crushers."