Isabelle Huppert, rehearsing a stage production of Virginia Woolf’s Orlando, is repeatedly stopped midspeech by director Robert Wilson, not because she’s botching her lines or misinterpreting the scene, but because…her hands don’t look right. That single clip from Katharina Otto-Bernstein’s documentary conveys pretty much all you need to know about Wilson’s approach to the theater. Whatever is pouring out of Huppert’s throat matters far less to him than the angle of her fingers, and this privileging of picture over content has helped make Wilson one of the world’s foremost avant-garde theatrical directors—as well as a cult leader who brooks no dissent in realizing his vision. A better title for this mostly admiring portrait might be “Absolutist Wilson,” but the film at least has the virtue of being shorter than Wilson’s own extravaganzas. (His aborted The Civil Wars project, conceived for the 1984 Summer Olympics, was slated to run 12 hours; an early ’70s “happening” on an Iranian mountaintop lasted a week and sent most of its cast to the hospital for dehydration.) Otto-Bernstein is quite good at linking the director’s haunting, glacial compositions—most notably showcased in Einstein on the Beach—to his childhood experiences as a stutterer. The only thing missing, really, from this rich sampling of the Wilson aesthetic is a sustained inquiry into that aesthetic’s limits. With the exception of dissenting critic John Simon, Otto-Bernstein’s interviewees never question Wilson’s theatrical universe, in which words are mere sounds, deaf and autistic children become fodder for dazzling stage pictures, and even political content—the evil that men inflict on one another—is transformed into the stuff of dreams.