Beginning with its title—You Cannot Start Without Me—Allan Miller’s portrait of Russian Maestro Valery Gergiev examines both the basic and abstract purposes that conductors serve, using Gergiev as a model of what elevates one to greatness. A pianist whose talent for conducting was identified during his years at a Russian conservatory, Gergiev rises through the ranks to become the artistic and general director of St. Petersburg’s Mariinsky Theatre. There, he shepherds operas and ballets through the volatile creative process, slogging through administrative muck and hearing out prima ballerinas during office-hour pow-wows. And yet, during performances, his job looks downright dangerous: Placed dead-center between stage and pit, Gergiev must both guide and react to the torrential performances surrounding him, and he seems to offer up his body completely, vibrating and thrashing like a weathervane. Footage from various rehearsals (Gergiev is imported to orchestras around the world, like a talisman) gives a strong sense of his struggle to locate and elicit the emotional effect he seeks from his musicians. Clearly treasured as a conductor, we learn comparatively little of the elusive, compelling Gergiev as a man—a workaholic, he admits missing out on much of his children’s lives, and his Putin sympathizing is given tantalizingly short shrift.