Sample This

Would Sample This have been more effective as a 30-minute short? Without question. But it is hard to walk away too disappointed when the stories are this fascinating—and when the music is this triumphant.

The movie provides a vivid sense of the period, as well as an intriguing backstage look at the making of improbable pop classics.

Even if you lack a wealth of rap knowledge, Sample This is still worth seeing. Like "20 Feet from Stardom" and "Standing in the Shadows of Motown," it focuses on the studio musicians whose contributions are well-known but whose identities are not.

The real pleasure of this film lies in its recognition of session artists and in the oddities and mysteries within the evolution of any given item of pop culture.

The music is incredible, and through interviews with Rosey Grier, Afrika Bambaataa, Questlove, and a squadron of old-school studio musicians, director Dan Forrer unearths some of the hidden history of American pop.

As an enjoyable documentary about the history behind a surprising game-changer of a song, this film works well. But it misses the opportunity to take its material to the next level and say something bigger.

The film offers disappointingly little insight into the music itself.