Bob Weir, “the other one,” steps into the spotlight and out of Grateful Dead bandmate Jerry Garcia's shadow in this expansive documentary. Only sixteen when he and Garcia formed the Warlocks, the group that would morph into the Dead, the rhythm guitarist, songwriter, and singer grew up on stage. As the house band for Ken Kesey and his Merry Pranksters' Acid Tests, the Dead experimented with LSD, fueling the development of its improvisational style and sustained jams. Weir estimates that he has performed in concert at least six thousand times, three thousand with the Grateful Dead alone. Weir's reminiscences; performance footage with and without the Dead; home movies; and interviews with family, friends, bandmates, and admiring musicians blend to form a film that is part biography, part Grateful Dead history, and part portrait of a cultural moment. “Sometimes the light's all shinin' on me,” the Grateful Dead sang in another signature line from “Truckin',” the song from which the film takes part of its title. In this engaging doc, the light shines on Bob Weir.