Katharina Otto-Bernstein’s documentary provides an excellent introduction to the singular vision of avant-garde stage director Robert Wilson. Its sketchy account of his career permits little insight into his ascent to mainstream venues over the past few decades, which hasn’t always been felicitous (also true of his collaborator Philip Glass). But Otto-Bernstein gives a sharp sense of Wilson’s comfortable Southern Baptist upbringing in Waco, Texas, and how his stuttering and learning disabilities shaped more radical aspects of his productions once he took on handicapped collaborators in works like Deafman’s Glance and A Letter From Queen Victoria. Wilson, Glass, Susan Sontag, and David Byrne are among the more perceptive interviewees, and the film includes many fascinating samples of his work. 105 min. a Music Box.