Serena Williams' post-Olympic Crip Walk victory dance doesn't make it into Maiken Baird and Michelle Major's documentary Venus and Serena, and neither does the subsequent ginned-up controversy. (The film centers on the sisters' 2011 comebacks.) But the outcry (and its analysis by Tumblr's brightest) lays bare the urgency of one of the film's urgent missions: an examination of the toxic reactions that have dogged the siblings since their first tennis-world triumphs. The doc combines rare news footage and home movies with much arresting new material: interviews; clips from their 2011 matches; and footage of them training, recovering from illnesses and goofily singing karaoke (a Venus obsession). The Williams clan is captivating, and best celebrity testimonials are blunt-- Chris Rock says the first time he saw the siblings he recognized that "they weren't country club black. They were black like I was used to"-- or dazzlingly self-serving, as with Bill Clinton's comment, "When I see a great athlete do something self-destructive, I always think we should cut them some slack." (That probably resembles an argument he's made in his own life.) It would take a miniseries to do justice to all the sisters have accomplished in the face of obvious obstacles and naked double standards, but what Venus and Serena does extraordinarily well is capture the work ethic and under-sung smarts of the sisters while taking viewers deep into their enviably close relationship. But the film isn't hagiography. The sisters are never denied their complexity or humanity, and Serena offers a comment that likely sums up her psychology better than volumes of ink ever could: "I hate losing more than I like winning."