Float like a butterfly and sting like a bee. This documentary film covers the period from 1964 to 1974, giving viewers a rare glimpse of America’s greatest fighter before he became a legend.

Muhammad Ali: The Greatest captures Ali in his most open moments (on the tour bus, in the changing rooms, and talking to fans and supporters), the film offers a portrait of Ali as a spectacular showman.

With an array of talking heads, the film builds up a historical picture of Ali’s influence. Yet it also confirms that he was as much a PR genius as a brilliant pugilist. As one university professor notes, Ali was the first ever spin doctor, a man who “fulfilled Madison Avenue at its best – or worst”.

Whether claiming “nothing is as great as me “, or getting the whole of Zaire to chant “Ali Boma Ye!” (“Ali Kill Him!”) during his fight with George Foreman, this was one boxer who knew how to work the crowd. Even as early as 1964, he was declaring “I’m the Champ!” and, on the basis of Klein’s documentary film, he wasn’t at all wrong.