In 1974, 18 years before MTV first assembled a group of comically mismatched 20-somethings and videotaped them being real, the choreographer Michael Bennett gathered 22 Broadway dancers late one night, set a tape recorder running, and asked them to talk about their lives. They did, telling moving tales of their career struggles, troubled childhoods, and sexual awakenings. Those stories, shaped by Bennett and his collaborators, became A Chorus Line, which opened at the Public Theater the next year, soon transferred to Broadway, and ran there for a then-unprecedented 15 years. James D. Stern and Adam Del Deo’s documentary juxtaposes the casting process for the 2006 revival with the affecting story of A Chorus Line‘s creation. Following several performers as they audition for the revival, the doc’s approach is designed, one presumes, to attract a wider audience in the era of reality entertainment. But while that meshes nicely with the arc of the musical itself—about dancers going through a grueling interview process to earn a spot on the line—we never learn enough about the individual subjects to care about their stories. For Chorus Line fans, though, the documentary—executive-produced, it’s worth noting, by theatrical superlawyer John Breglio, who also produced the revival and controls Bennett’s estate—is a singular sensation, filled with behind-the-scenes backstory and archival clips of Bennett himself dancing, gorgeously. Then there are those original interview tapes, kept under lock and key for 35 years, with the dancers speaking the words that, up to now, you’ve only known as lyrics.