The documentary ‘Scott Walker: 30 Century Man’ profiles the influential but obscure musician.

The early scenes of the documentary look like some lost reel from "This Is Spinal Tap," spanning what seems like half of rock history -- complete with hem lengths and haircuts.

But the protagonist is not a metalhead but a Zelig-like figure: Here he is as a squeaky-clean pop idol in the Frankie Avalon mode, gazing bashfully. He shows up on L.A.'s Sunset Strip at its wildest. Next he's part of a mop-topped boy band in swinging London. Then he's an artsy songwriter brooding behind scarves and cool shades. Finally, he's a baritone singer who combines depression with extravagant theatricality -- a sort of Leonard Cohen gone Vegas.

Just who is this guy? For the uninitiated, he's Scott Walker -- born Noel Scott Engel in small-town Ohio. And now, at 66, he continues to be the reclusive hero to Brit rockers, hipster intellectuals, Mojo magazine readers and swooning sexagenarian German women. But he remains a mystery to nearly all.

Even David Bowie, a longtime fan, feigns bafflement during his on-screen appearance in "Scott Walker: 30 Century Man," a documentary opening Friday at the Nuart Theatre in West Los Angeles. "Why, I don't know anything," he offers with a sly smile. "Who knows anything about Scott Walker?"