"One Singular Sensation"

New York -- Dancer Rachelle Rak climbs "up a steep and very narrow stairway" to a dressing room at the Broadhurst Theatre to await the worst news of her professional life: She will not be getting the role of Sheila in the Broadway revival of "A Chorus Line," an ambition she has poured her whole life into, not to mention the rigorous eight months of the audition itself. "It's all good," she gamely tells Jay Binder, the casting director, as she fumbles for her dance bag, only too aware that cameras are recording every humiliating moment.

Indeed, those cameras recorded more than 500 hours of the audition process for the revival of the landmark musical created by the late Michael Bennett. The result is the new documentary "Every Little Step," which opens Friday. The $2-million movie about actors auditioning for a musical is a multilayered, fugue-like celebration not only of what it means to be a professional dancer on Broadway but also of the iconic musical that captured it so well.

"I thought to myself at the time, 'Why did I ever sign that waiver?' " recalls Rak, looking back to January 2006 and commenting on the fact that the Actors' Equity union had given permission for cameras to film auditions for the first time ever. "But now I think: Why not? If the audience is able to see all the joy, passion and heart that I put into the audition, then why not the pain and disappointment too. That's all part of the story."

As delineated in "Every Little Step," that "story" started on a snowy night in January 1974 when Bennett gathered 22 dancers for an all-night soul-baring session that would become the basis for the longest-running American musical in history. The documentary kinetically interweaves the casting of the revival -- winnowed from 3,000 applicants -- with rare archival footage and interviews with the original creators, including star Donna McKechnie, composer Marvin Hamlisch, and Bennett associate and friend Bob Avian.