Picture Herbie Hancock in 1973. He’s been a jazz star for a dozen or so years. In fact, he’s played in one of the greatest groups in the genre’s history, Miles Davis’ Second Great Quintet, where he helped jazz incorporate wild new ideas without losing its plot. And when Miles wanted to push it even further, Herbie joined him, plugging in an electric piano and crumbling whatever superficial structures separated jazz from acid rock and funk and even ambient music on a series of revolutionary records. The form they cracked open in Bitches Brew released a new spirit, and Herbie chased it into the atmosphere. And now, in 1973, he is the leader of one of the farthest-out groups of all time—the mighty Mwandishi, explorers of deep outer space. He’s helped to reshape jazz three or four times already. And he’s only 33 years old. If he were to retire today, he would already go down as one of the most important musicians of the 20th century...and he’s completely undone by the Pointer Sisters.

The Oakland R&B group was, at the time, climbing the charts on the back of “Yes We Can Can,” a thick, patient, interlocking piece of pop-funk written by the great Allen Toussaint. The Pointers opened for Mwandishi at the Troubadour in West Hollywood and had the entire room up, stomping, clapping, sweating. How could the cosmos ever compare to the specter of several hundred people dancing together in a steaming club?

There had never been a band like Mwandishi before. But when you follow your muse that far out, it can be hard for people to come along. The up-close views of Mars are unforgettable, but it’s hard to connect when you’re wearing a space suit. And Herbie wanted desperately to connect. “My philosophy of music changed,” he told the Baltimore Afro-American in 1976. “What I discovered is that my music wasn’t functional. It wasn’t dinner music, it wasn’t party music, it wasn’t music with which you could have a conversation with someone.” The lack of gravitational pull might make things seem light, but in that deoxygenated darkness, distant from the earthy Black funk of the Pointers and Funkadelic and Isaac Hayes—to say nothing of the liberating cri de coeur of Sly and the Family Stone’s “Thank You (Falettinme Be Mice Elf Agin)”—the Mwandishi music felt leaden. “I was beginning to feel that we were playing this heavy kind of music, and I was tired of everything being so heavy,” he said.

So Herbie lightened up. He let most of his band go, keeping only saxophonist Bennie Maupin. He poached drummer Harvey Mason from his old boss Donald Byrd. He plucked bassist Paul Jackson from an obscure Santana side project. Percussionist Bill Summers had played on a single track by Jerry Garcia associate Merl Saunders. The band they’d eventually call Headhunters couldn’t have been much farther from jazz orthodoxy if they’d tried. For old heads attuned to the evolution of the genre, it wasn’t exactly the Third Great Quintet.

Head Hunters, the only album this band ever made together, is one of the greatest jazz albums of all time. It’s also one of the greatest funk albums of all time. It shaped the course of both genres—and R&B, and eventually hip-hop—breaking down perceived barriers between art music and pop music. Fifty years later, its influence can still be felt in everything from Trombone Shorty’s big-tent brass-rock to J Dilla’s collagist hip-hop to the UK drum ’n’ bass workouts of Roni Size & Reprazent. Flying Lotus, Thundercat, Kendrick Lamar on To Pimp A Butterfly, Kamasi Washington, Terrace Martin, Robert Glasper—these are just current L.A. musicians working in Head Hunters’ shadow. Mason’s slap-back drumming and Herbie’s oozing synth lines have been sampled by pop stars (Madonna), rappers (Digable Planets, Tupac, LL Cool J, Ice Cube), trip-hop legends (Massive Attack), rock weirdos (Frank Zappa), titans of dub (The Upsetters), and titans of basketball (Shaquille O’Neal). It is exceedingly rare that an album is actually as good as music critics, history, and its fans insist it is. If anything, Head Hunters is even better.

It’s also informed by some of the ideas he’d pursued years before. Miles Davis’ 1969 album In A Silent Way, which Herbie contributed to, was composed of long jams that were then shaped and layered in postproduction—a common technique in rock and pop music of the time, but controversial in jazz, where live improvisation and spontaneous group energy reigned supreme. Herbie brought this cut-and-shape ethos to Head Hunters, and it allowed him to create interplay at a meta level. Though the concept hadn’t quite made its way into popular jazz at the time, the band treats their lines almost like tape loops, playing the same phrases repeatedly without much elaboration. Through sheer repetition and clever juxtaposition, sounds that have been repeated any number of times appear to evolve and deepen.

Herbie had written “Watermelon Man” 10 years earlier for his 1962 solo debut Takin’ Off, but the version on Head Hunters appears in dramatically different form. It opens with Summers blowing a ducking and diving pattern across the top of a beer bottle, simulating the sound of a Cameroonian flute. The rest of the Headhunters join in with blowing, whistling, yipping, their individual rhythms percolating into a single unit as complex and round as a mound of soap bubbles. Jackson plays a clipped bass line that neatly predicts the method hip-hop producers would use to sample records like this one 20 years later—his riff sounds like the best and most idiosyncratic moment in a longer solo that he’s isolated and turned into the song’s spine. By the time Herbie comes in with a clavinet keyboard line as sharp as rose thorns, Mason is anchoring a cubist beat that feels like five rhythms and one at the same time, all of it anchored by Summers’ beer bottle. Suddenly, all this sound gathers into a single strike, the whistling disappears, and “Watermelon Man” begins to sound like something closer to a traditional jazz song. When the beer-bottle melody returns much later in the song and the yipping and whistling are layered back in, the patterns they’re playing haven’t changed from the song’s beginning, but the air around them—and thus the way we hear them—carries a different charge. It’s a masterful arrangement.

All this repetition confounded some critics and more traditionally minded musicians. The Associated Press accused Herbie of “playing schlock,” while DownBeat’s Gary Larson, reviewing a live Headhunters show shortly after the album’s release, wrote, “The band tends to get caught in an up-tempo groove and remain there for the entire set.” For Larson, all that power came at a perceived cost: “The subtlety of previous Hancock groups is notably absent,” he wrote. Even leaving aside the racially charged notion that rhythmic subtlety is less sophisticated than melodic subtlety, an old head might have said that Headhunters’ focus on groove meant the music wasn’t developing and it wasn’t doing anything, and therefore it wasn’t exploratory. But Herbie—and John and Alice Coltrane, and Pharoah Sanders, and any other Black artist who by 1973 had sought their own reflection in West African music and culture—had discovered a secret. There can be great profundity in repetition. There can be great profundity in moving your body.

“There are two ways to listen to monotony,” Herbie told the great jazz critic Leonard Feather around this time. “It can be looked on as boring repetition—or it can be boring a hole straight through into your mind.” It’s the famous decree Funkadelic had issued three years prior put in reverse: Free your ass, and your mind will follow. “It’s simpler, true,” Herbie conceded, “but I wouldn’t say that the intellectualization of music necessarily improves it; nor does the voicing of horns in a manner more complex than what I’m now using. It’s a matter of personal taste, which has nothing to do with the value of the music.”

But in 1973, many, many people’s personal taste suggested that there was something valuable about this music. A truncated version of “Chameleon” was a certified hit, charting on Top R&B Singles and the Hot 100. The album went gold, selling 500,000 copies six months after it was released—a feat that took Miles Davis’ epochal Kind of Blue 35 years to achieve. It became the first jazz album to sell 1 million copies. It’s not hard to understand why: Mason’s drumming is so good that his isolated tracks could’ve sold 100,000 copies on their own.

More important, Head Hunters connected Herbie to his audience in a way he’d never experienced. “It’s a pleasure…to walk out on stage and see a packed house actually dancing to your music,” he told Feather. “All the audiences I played to [before] were 80 to 90 percent white. Finally, I’ve been able to come out with some music the general black public can relate to.”

There they are, Headhunters, on Soul Train, in September 1974, playing “Chameleon” for Don Cornelius and what musicologist Steven F. Pond called “a young, hip, black listenership that had largely come to yawn at jazz.” The Black press understood the album instantly: “Head Hunters is BAD. The album for the most part is Funkaay,” wrote the Atlanta Panther. “This album is a monster. If this is any indication of Herbie’s new sound, I welcome the change.”

Head Hunters wasn’t just a new direction for Herbie. At a time when jazz fans worried about the genre’s relevance and future, Herbie and his new band—along with fusion groups like Return to Forever, Weather Report, The Tony Williams Lifetime, and Ornette Coleman’s Prime Time—showed a way to incorporate ideas from the worlds of funk and pop and rock to bring jazz forward. By making “dance music for the cerebrum,” as one writer put it, Herbie showed that the genre could converse with other styles without losing its soul.

“The thing that keeps jazz alive, even if it’s under the radar, is that it is so free and so open to not only lend its influence to other genres, but to borrow and be influenced by other genres,” Herbie told The New York Times’ Nate Chinen in 2013. “That’s the way it breathes.”

Jazz inhales music from around the world, and it exhales a new jazz back into that world. Breathe enough and it may start to seem natural, normal, a vital exchange in the most literal sense of the term. Something so close to the source of life it can be hard not to take it for granted. You may be so busy dancing to the music, you forget you’re breathing at all.