Possessed of a lugubrious, histrionic baritone that could make the most trifling of pop ditties sound like a slow dance on the brink of apocalypse, Scott Walker may be the unlikeliest figure to maintain any presence on oldies radio, thanks to the Walker Brothers’ majestically despondent 1966 smash, “The Sun Ain’t Gonna Shine Anymore.” From the increasingly experimental solo records that followed, and Walker’s subsequent reputation as a reclusive genius and cult figure, you’d expect the subject of Stephen Kijak’s documentary to be a forbidding, pretentious artiste—and the pleasant surprise of Kijak’s film is that he’s anything but. Ignore the movie’s occasional heavy-breathing narration and Willy Wonka–esque graphics: In down-to-earth interviews all the more precious for their rarity, the Ohio-born teen idol turned industrial-cabaret innovator comes across not as a Jandek-like eccentric or obscurantist but as a man trying to realize abstract visions through exacting concrete means. And if that means demanding retakes of a percussionist punching a side of meat (for Walker’s 2006 album, The Drift), Kijak lets the results speak eloquently for themselves. Admirers and followers ranging from David Bowie (the movie’s executive producer) and Brian Eno to Radiohead and Pulp’s suavely arch Jarvis Cocker testify to Walker’s originality and importance, but for fans, the doc’s biggest revelation may be the extent of his stardom, even as he began to explore bawdy Jacques Brel chansons and psychedelic dada crooning. In England, the Walker Brothers rivaled and perhaps surpassed the Beatles in popularity, and Kijak amasses evidence (including electrifying BBC performance clips) to show that Walker’s teeny-bopper audience followed his experimentation, at least for three initial solo albums. Given Walker’s notoriously unhurried methods, footage of him consulting with Leos Carax about the scoring of the director’s gloriously mad Pola X are like glimpses of an obsessive’s Olympus—the next best thing to witnessing a powwow between Phil Spector and Werner Herzog.