It must say something about something that Cocksucker Blues, the Rolling Stones’ never-released 1972 tour documentary, which has existed mainly as a salacious rumor for 40 years, was screened at New York’s Museum of Modern Art on Thursday night, as part of a Stones film retrospective.

Bootlegged bits of the movie have surfaced over the years, and the whole thing was illicitly posted a few months back on YouTube, where it looks cruddy. So at MoMA, I was expecting vintage junk. But seeing the picture on a big screen was, it must be said, a revelation. Apart from the hot stuff of legend—the desultory smack-shooting, the raw groupie-banging—the movie’s real subject is the exhaustion and monotony of life on the road, and the exhilaration of those few hours onstage every night that make it all, or almost, worthwhile. The film’s technical cruddiness might almost be a formal strategy—the drugged-out rhythms draw us in and slowly work us over.

For those who may think of the Rolling Stones—if they think of them at all—as a superannuated joke at this point, it’s instructive to be reminded what a powerful band they were. And how, as we see here, they transformed not just pop music, but the pop-music business.

After the group’s original lineup solidified in early 1963 with the addition of Charlie Watts to the core unit of Mick Jagger, Keith Richards, Brian Jones and Bill Wyman, the band signed with Decca Records—an old-line British label that had passed on the Beatles the year before, and wasn’t about to be caught looking stupid a second time. The Stones started scoring hits right out of the gate, and broke through worldwide in 1965 with “(I Can’t Get No) Satisfaction.” The hits kept getting bigger—“Paint It Black,” “Jumpin’ Jack Flash,” “Honky Tonk Women”—and the Stones, marketed as a sort of anti-Beatles, began forging a new template for the rock-star lifestyle: concert riots, pot busts, even a dab of jail time. It was a big deal back then, but I’ll bore you no more.

The band’s contract with Decca expired in 1970, and the Stones were ready to break free and start their own label. Before they could, though, Decca reminded them that they owed the company one last single. Irritated, no doubt, the group turned in a track called “Cocksucker Blues,” which was of course immediately shelved. (Bootlegs, if it need be said, can still be found.)

One of the earliest scenes in Cocksucker Blues, the movie, shows Jagger bent over a piano in some anonymous hotel room, plonking away at this very song. The scene is being captured by Robert Frank, a Swiss-born photographer and experimental filmmaker with connections to Jack Kerouac and Allen Ginsberg and, thus, serious avant-garde cred. The Stones had invited Frank to document their latest tour—the first since their 1969 outing, which had ended in a bonfire of bad vibes at the Altamont Speedway in Northern California. Frank brought along noisy 16mm cameras, some of which he reportedly left lying around for the use of anyone who felt inspired to preserve the tour’s endless, soul-draining downtime.

And here it all comes: the giggling groupies being relieved of their clothes in the front of the band’s private jet; the naked woman sprawled on a bed with her legs splayed and her chest covered with what appears to be semen, chattering directly to the camera. We see a number of people quietly shooting heroin, and, in a classic moment, Keith Richards slowly nodding out on a backstage bench in the lap of a groupie, who soon slumps over, too. In the fan world outside one concert, we meet a hard-bitten woman who tells us her baby was taken away from her because of her heavy use of LSD. She finds this unfair: “He was born on acid,” she says.

It should be noted here that an introductory message at the beginning of the film claims that what we’re seeing is fictitious. That it was all…what, staged? Whatever. Anyone who has whiled away dead hours in the company of nattering drug monkeys, or encountered women who will happily get down, not with the stars, but with the crew, will recognize what’s going on here as real-world behavior.

The Stones’ 1972 tour was more than just the traditional record promotion (in this case for their new album, Exile on Main Street). It was a celebration of the new rock-star high life—a garish weave of low-rent rock and roll and high-society interloping. Champagne flows, bottles of Jack and endless joints pass back and forth, star-struck rock journalists wander through asking unbelievably inane questions. Room-service orders founder in druggy incomprehension. Keith Richards drops a TV off a tenth-floor balcony. The air is thick with fatigue and ennui, and no less so when we start spotting the rich and famous of the day: Is that Truman Capote? Andy Warhol? Terry Southern? What’s Dick Cavett doing here? 

The movie bears deadpan witness to all of this, and as we sink into its long takes and slugged pacing, we marvel at the director’s refusal to goose things along with fancy cutting or time-compressing montages. This is what happened, we’re told, and this is how it happened. The drifting enervation is a substantial part of the story.

Which would be a drag, maybe, if that were all there was to the movie. But we get a lot of performance footage, too, and some of it is electrifying. The coverage is old-school: one or two camera positions for the most part. But as the band churns out “Midnight Rambler” and “Happy” and “You Can’t Always Get What You Want” (no “Sympathy for the Devil”—that song was retired after Altamont), you can see the weary cynicism of some of the backstage scenes drain from the musicians’ faces. They’re reaching the outer limits of their youth (Jagger and Richards were both 28 years old on this tour), but they’re not yet capable of faking their love of music. And the sequence in which opening act Stevie Wonder comes out to join the Stones for an encore of Wonder’s “Uptight (Everything’s Alright)” is one of the great transporting moments of rock-on-film. Were these brief nightly peaks worth enduring the vast bottomlands of boredom that surrounded them? Hey, probably. Along with the attendant cash avalanches? Is that a question?

(MoMA’s Rolling Stones restrospective, showcasing such films as Gimme Shelter, Rock and Roll Circus, The T.A.M.I. Show, and Godard’s Sympathy for the Devil, runs through December 2.)