It is difficult to find anything new to show or tell about Muhammad Ali, perhaps the most well-documented sports life of the 20th century.
And indeed much of the material in "I Am Ali," which premiered in limited release Friday, will be familiar to avid sports fans of a certain age -- even though vintage footage of The Greatest always is a compelling watch.
The wrinkle this time around is a more complete picture of his family life, including his relationships with his nine children, and in particular, clips of intimate voice mails he left for them over the years.
Maryum "May May" Ali, the eldest of the nine, told Newsday her father never has been much for giving his children boxing memorabilia, but he felt strongly about them controlling the tape recordings.
"Trunks, gloves, the kids don't really own anything; we'd have to go on eBay and buy it," she said. "These tapes were the only things where he said, 'I want my kids to have this and no one else.' "
Muhammad gave his daughter Hana about 80 hours of taped calls to assorted people in his life -- on not only family matters but also world events. She is saving most of the material for a project of her own, but she offered about 12 minutes' worth to "I Am Ali" director Clare Lewins.
May May said the family is pleased with the result because it shows another side of the famed boxer.
"Most journalists did not see the value in his children; they were so stuck on the sport and the social activism," she said. "At the end of the day after every fight, every headline, was the family, and he confided in us and talked to us.
"This is the first movie where people can relate to him as a father. That's hard to do when you have ex-wives who are scorned, who are mad, who are upset. He had to deal with a lot of the negativity coming from the women.
"It's not a movie that says he's a perfect person. It shows a man in his evolution. It's the essence of my dad's spirit that protrudes out of the screen."
May May said her father was "a bit addicted to recording. It was something he owned. He didn't own the footage of his fights. This was personal."
Ali does not appear in the film. At 72, he continues to suffer the effects of Parkinson's disease.
"It's a progressive disease that changes over time whether you like it or not," May May said. "He's not bedridden. He's not in pain. Parkinson's has slowly taken away his voluntary movements. It is what it is."