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What: “Bud Greenspan’s Kings of the Ring”

Where: Showtime

When: Tonight, 10

Bud Greenspan, the Olympic documentarian, has ventured into the boxing ring and scored a knockout with this 1 1/2-hour special on four heavyweights--Jack Johnson, Jack Dempsey, Joe Louis and Muhammad Ali.

In words written by Greenspan, narrator Will Lyman tells us these four men “are among those few who stood above the rest, men who captivated the public in and out of the ring to become legends for all time.”

As with most Greenspan films, this documentary is about more than simply athletes and their accomplishments. It’s about history, social injustices and society in general, with sport, in this case boxing, as the backdrop. Boxing fans will love this, and so should history buffs.

Some of the anecdotes are known, some are not. Some of the footage you’ve seen, some you have not. The film consists of four separate stories, but they are intertwined as viewers are taken from the blatant racism experienced by Johnson in the early 1900s to the more subtle racism of the 1960s when Ali was severely criticized by whites for refusing to enter the military draft. The film ends with Ali lighting the torch at the 1996 Summer Olympics in Atlanta.

Johnson was an African American who shocked and challenged white America with his prowess in the ring and his defiance of social convention. He taunted his beaten opponents. He dated and married white women. David Remnick, an editor of the New Yorker, called Johnson “one of the most culturally sophisticated figures in the history of boxing; he loved music and the theater, he had a taste for fine wine and he spoke French and Spanish.” He drove race cars and owned a club that served liquor during Prohibition. Included is footage of Johnson, in later years, conducting a jazz orchestra. And there is incredible footage of his most noteworthy fights, including his victory over Canada’s Tommy Burns in Sydney, Australia, in 1908, and his pounding of Stanley Ketchell, the “Michigan Assassin,” in 1909.

The segment on Dempsey includes his “long count” fight with Gene Tunney at Chicago’s Soldier Field in 1927. The Louis-Max Schmeling fights are chronicled, as are the Ali-Joe Frazier fights and much more.