For a self-styled goth-punk gargoyle, Nick Cave has aged magnificently. Now 56, he seems like a man who might frighten young children, as prologue to inspiring them. In Iain Forsyth and Jane Pollard’s overdue-seeming documentary, a cool spellbinder that stages a day in Cave’s creative life, he plays himself and has a writing credit, which means saying things like, “At the end of the 20th century, I ceased to be a human being. That’s not necessarily a bad thing. It’s just a thing.” Erik Wilson’s cinematography is aptly dusky and studious, and the film gets a bit precious with its gloomy-daydream flow, but a more straightforward chronicle obviously would have missed its target. The main interview being conducted here is psychiatric: Cave sits with a shrink, probing early memories of, say, dressing in female clothes, or hearing his father reading Nabokov’s Lolita aloud for the sake of language appreciation. There’s also some telling interaction with Cave’s current and former fellow Bad Seeds, plus qualified character witnesses including Ray Winstone and Kylie Minogue. Most fascinating is of course the man himself: For all of that commanding stage presence, and there’s a lot of it, he’s never above vamping unguardedly at a piano and being told his chord progression sounds like Lionel Richie’s. At this movie’s dark heart is the disarming self-awareness and intelligence with which Cave cops to raiding, mythologizing, and cannibalizing his memories, be they exquisite or banal. The mystique endures, as does some very practical wisdom on the matter of how to be an artist.