I found Summer of Soul tremendously moving — both exhilarating and enraging. Your results may vary, but there’s no way you can find it any less than incredibly interesting. The film’s parenthetical subtitle, (…or, When the Revolution Could Not Be Televised), refers to the incendiary 1970 song “The Revolution Will Not Be Televised” by jazz musician and poet Gil Scott-Heron. It also refers to the fact that, until now, no audience has seen this film footage since it was recorded over fifty years ago.

Directed by Questlove, Summer of Soul assembles the long-lost footage of the 1969 Harlem Cultural Festival at Mount Morris Park, a six-part, six-week concert series free to all featuring some of the most awesome musical talent in the world: Nina Simone, Stevie Wonder, Mahalia Jackson, B. B. King, Sly and the Family Stone, Gladys Knight & the Pips, the Staple Singers, and on and on. There was a whole day of just gospel music, a whole day of Motown. The richness of the black music tradition in America is almost overwhelmingly expansive, encompassing blues, jazz, gospel, pop, rock, funk — and the global influences are so vast — that a sixty-part concert series could hardly have covered it.

The Black Panthers provided security, sidelining the police force. With a mostly black audience of up to three hundred thousand — young and old, elderly gents in sleek suits and hats and young hipsters in glorious afros and tight, low-cut jeans, and so many children, whole families there, some people sitting in the trees to get a better view — this epic event seems made to be remembered.

And yet, as commentators sadly attest at the end, it was all quickly forgotten. The footage was shot with the intention of making a concert film — joining the ranks of that era’s classics like Woodstock, Monterey Pop, and Gimme Shelter — but garnered no interest from producers at the time.

Why? Because Woodstock happened less than a hundred miles away around the same time, and that’s all the media was talking about. “We even tried calling it ‘Black Woodstock,’” says producer and videographer Hal Tulchin, “but it didn’t help.”

The festival was created on a shoestring budget so tight they couldn’t even afford a full lighting package, so the stage had to be built facing the glaring heat of the summer sun. Festival director and producer Tony Lawrence pulled it together through sheer charisma and promotional savvy, plus a sponsorship he scored from Maxwell House coffee — and in the film we see the brand’s embarrassing commercial ad of that era, with its exaggerated “African” emphasis in voice-over telling about the deep, rich soil of the “dark continent” where the coffee beans supposedly grow.

Throughout the film, Questlove breaks out of the concert footage with regular montage sequences dealing with the many related subjects called up by the staging of the event: the performers’ histories, the memories of the experience of the concertgoers (many of whom are interviewed), the social context of the time which was both excitingly volatile and hugely tragic, with the assassinations of Medgar Evans, Malcolm X, and, very recently at the time of the concert, Martin Luther King Jr. These are brought front and center at the festival when Jesse Jackson takes the stage to introduce gospel legend Mahalia Jackson and saxophonist Ben Branch. He reminds the crowd that Ben Branch was with him and MLK Jr the day of the latter’s assassination, and that King had asked Branch to “be sure to play my favorite song.”

It’s a real gut-wrencher, as it’s meant to be. Mavis Staples says, in her interview, that Mahalia Jackson — quite elderly at the time — wasn’t feeling well that day, and asked her to join in and help with the vocals. The performers were quite aware of the historical significance of what they were doing not just politically, but musically as well, as Jackson passed the torch, in the form of the microphone, to Staples.

The Apollo moon landing also took place during the festival — 1969 was a year when everything was happening at once — and Questlove designs a telling montage of responses by white and black citizens to that extraordinary event. As you might expect, the white response is uniformly enthusiastic whereas the black response is much more equivocal, or downright hostile. “I think it’s very important, but this [festival] is equally important.” “Never mind the moon, let’s get some of that cash in Harlem.” “It’s a waste of money, people going hungry all over the USA . . .”

This is an extraordinarily topical sequence now, with billionaires funding rockets to fly into space, while memes fly around social media quoting Gil Scott-Heron’s bitter song “Whitey on the Moon”: “I can’t pay no doctor bill. / (but Whitey’s on the Moon.)”

There’s so much happening in the film, it’s hard to know what to single out, but one thing you won’t be able to ignore is the clothes. Oh my God, the clothes. As narrating voices point out, the look associated with Motown, elegant suits and gowns, extravagantly coiffed hair, all very “classy,” was transitioning to defiant natural hair and hugely inventive outfits — fringed, ruffled, wildly accessorized — in deliberately shocking colors, often drawing on African and Latino influences.

A good example of the transition between phases, musically and sartorially, is Stevie Wonder, just beginning to expand on the Motown performance style that first brought him fame as the child prodigy Little Stevie Wonder, to become more daringly improvisational as well as political. He looks fabulous in a brown suit with the most amazing stand-up collar of almost Count Dracula height and a sun-yellow ruffled shirt. And there’s also David Ruffin, who’d recently left the Temptations, taking the stage to sing their enormous Motown hit “My Girl” by himself. Remarkably tall and thin, he’s left behind his old band’s trademarked tuxedos for a narrow-cut black suit with a pink shirt and a major fur collar like Joan Crawford might have once worn.

Men’s clothes in particular stand out in this film, casting off or at least wildly embellishing the suits in drab colors that had long been mandated in “polite” American society. Impresario Tony Lawrence wears a series of arresting shirts, with my favorite being the elaborately ruffled hot-pink satin one, cut — as they used to say — down to there.

Then of course there’s Nina Simone. As one witness attested, “She looked like an African princess,” with a tower of elaborately braided hair, giant hoop earrings of complex design, and a boldly patterned, floor-length green halter dress. When she comes out, sits down at that grand piano, and hits those keys so hard that you see the muscles jump in her arms, it’s hair-raising.

And she’s talking real revolution, no doubt about it. The lyrics to her call-and-response song “Are You Ready?” aren’t asking if you’re ready to rock. They’re asking, “Are you ready to do what’s necessary? Are you ready to smash white things, to burn buildings, are you ready?”

When Sly and the Family Stone casually assemble themselves onstage, taking their time to tune their instruments, it’s probably in part just to give everybody time to take in the multiracial ensemble defying all sorts of conventions. “To see a black woman playing a trumpet,” marvels a concertgoer of Cynthia Robinson, the band’s formidable trumpet player and backup singer. And regarding Greg Errico, the white drummer wearing an outrageous all-leopard-print getup: “The white guy’s the drummer?!”

We watch the massive crowd waiting with bated breath to see if Sly Stone will actually come out or skip the whole thing — you never knew for sure at that time — but when he finally does emerge, in maximum style as always, he throws back his head to sing that fantastic chorus of “Everyday People—“IIII-HIGH-HIGH love everyday people, yeah yeah,” — well, I just about wept.

I also just about wept, but in a different way, when I looked into this the film’s producing entity, the Onyx Collective, which appears in the opening credits. But far from being an actual collective of independent black filmmakers, you should know Onyx is in fact a “curated content brand at Disney” for “creators of color and underrepresented voices.”

Summer of Soul is the first Onyx feature. And the second? The 1619 Project, to be produced by Oprah Winfrey.

Yeah, Disney owns everything. And their “revolution” will definitely be televised.