Roger Waters heard what everyone in Genesis was saying about him. In a 1975 interview around the release of Wish You Were Here, the Pink Floyd bassist and vocalist responded to his peers’ suggestion that they were aiming for real art, while Pink Floyd, whose records were now selling in the millions, had grown more interested in appealing to the lowest common denominator and fading into the background.

While the word “diplomatic” is rarely used to describe Waters, he managed to address this criticism with a distinct lack of rancor. Here’s what he posits: Unlikely scenario, but, if someday Genesis—a whimsical prog band who just lost their visionary frontman and who would, within a year, release an album partially inspired by the novels of Emily Brontë—someday achieve the mainstream success enjoyed by Pink Floyd—a band so popular that characterizing them as “prog” feels somewhat minimizing, like calling Star Wars a “sci-fi” film—then there’s a good chance that they, too, would loosen their distinctions between high and low art.

Then in his early 30s, Waters was testing a theory about how rock stars might age gracefully in this miserable industry. It had been less than a decade since Pink Floyd’s artful and inventive debut, 1967’s The Piper at the Gates of Dawn, but they had already endured enough transformations, upended so many expectations, and achieved so many artistic highs as to feel like their best work could well be behind them. Looking back on the massive success of 1973’s The Dark Side of the Moon—a commercial and creative breakthrough that changed their lives forever—he came to understand what makes art connect with the masses. For better or worse, he decided, people were attracted to the chase: the ambition that drives us to even believe we could make something like Dark Side of the Moon. Once you do it, the story is over. “Wish You Were Here,” he explains, “came about by us going on in spite of the fact we’d finished.”

At first, the creative process was just as labored as he makes it sound. The band—Waters, David Gilmour on guitar and vocals, Richard Wright on keys, Nick Mason on drums—was lost. Distracted. New songs emerged but they lacked any unifying theme. When they tested new material on the road, music journalists did what we sometimes do, which is to turn our backs on good bands when they get too popular, relitigate them based on their fame, and suggest the edge is gone—if there ever was an edge!—and, at the very least, the thing that once felt like magic has started to become stale. “The Floyd in fact seem so incredibly tired and seemingly bereft of true creative ideas,” Nick Kent wrote in a 1974 issue of NME, “one wonders if they really care about their music anymore.”

The band was no stranger to bad reviews but this one got under their skin. As they gathered in the studio in the early days of 1975, they had to concede that maybe Kent had a point. They showed up late. They bailed early to play tennis. There was a eureka moment near the beginning to make a concept album called Household Objects using no traditional musical instruments whatsoever, a relatable impulse for anyone who only has to see their laptop sitting on their desk to start stressing about all the work they should be doing. So there they were at Abbey Road Studios, filling their wine glasses at various levels, rubbing their fingers along the rims, gazing expectantly into each others’ eyes, hoping to strike some magic chord. There were times when it seemed like Pink Floyd had no choice but to call it a day.

There were also four notes: B-flat, F, G, E, played with eerie delay on electric guitar by Gilmour. Waters heard the melody—strange, gorgeous, unresolved in a way that felt both tragic and full of potential—and thought of Syd Barrett. The band’s co-founding member and former vocalist had parted ways at the end of the ’60s due to his deteriorating mental health, just before Pink Floyd achieved the mainstream success that was now driving them to the point of paralysis. While the rest of the band was accepting of the type of lifestyle change that allowed Mason to partner with his Aston Martin specialist to open up the luxury auto shop he always dreamed about, Barrett was on a different path entirely: making artsy music for a cult audience, receding into grim isolation, developing a mythology as the raw heart of a sound he was too pure to sell.

Immediately upon release, Pink Floyd described Wish You Were Here as an album about “absence,” and that central “absence” was Barrett. As soon as Waters wrote the words to accompany Gilmour’s guitar riff, this idea evolved to form the album’s bookending tracks, altogether 25 minutes of music called “Shine on You Crazy Diamond.” In these songs, Waters summons Barrett’s spirit like some kind of Greek deity, calling on his creativity and restlessness to guide them forward. “You were caught in the crossfire of childhood and stardom,” he sings, “blown on the steel breeze.” For my money, these songs contain some of the most inspired rock’n’roll poetry of the ’70s, words that use the band’s immense fame to their advantage: a pathos gained from our awareness of precisely who he’s singing about. And if we don’t know, Wright eventually interpolates a motif from Barrett’s “See Emily Play” in its closing moments to draw the connection for us.

In this way, Wish You Were Here marked a new kind of creative breakthrough for a rock band in the ’70s. This was the same year that Bob Dylan turned his lens inward on the introspective, seemingly autobiographical Blood on the Tracks, inviting his audience to dispense the mythology and hear him as a real human being with real, aching human emotions. So it goes with Wish You Were Here, where Pink Floyd write elegies for their own history and bemoan the zombies and vampires now surrounding them. If Dark Side achieved transcendence by exploring the human condition through the cosmic, timeless lens of interspace travel, here was a dark night of the soul described through lonely recording sessions, jam sessions with the radio, and helpless conversations in boardrooms: “Oh by the way, which one’s Pink?” goes an oft-quoted line in “Have a Cigar,” one of the only moments of levity on an album otherwise dominated by mournful, psychedelic wandering.

Tellingly, this track is sung by a musician outside of the band—one of several ways they used their artistic stagnation to their advantage. When neither Gilmour nor Waters felt capable of delivering the sneering line with the right amount of energy for the part—in the overarching concept, the kind of industry vulture whose obsession with productivity hastened Barrett’s descent—they invited songwriter Roy Harper, working on his own album down the hall. The outsider presence just slightly widens the frame of Wish You Were Here, loosening the purview and deepening the drama of a band losing faith in its own abilities. (The self-doubt didn’t last long: Waters soon affirmed in the press he could have done it better himself if he had just a bit more time.)

With Pink Floyd playing as a backing band for Harper, “Have a Cigar” exposes the group’s strength as a singular unit by the mid-’70s—road-tested and explosive, no longer guided by the acid-soaked spirit of their early years, nor by anything to which you could apply the descriptor “playful.” They performed slow, serene, steady. Where Waters sings his songs in a stately voice that always seems to demand poetic gravitas, even when you don’t really know what he’s singing about, Gilmour tends to stretch his voice to the top of his register, illustrating the human stakes of his stories. In the largely drumless “Welcome to the Machine,” his wailing over Wright’s orchestra of Minimoog and Hammond organ gives the sense of someone shouting to be heard through a heavy windstorm. Often on Wish You Were Here, Pink Floyd seems to be testing just how long they could stand in one place as forces push against them from all sides.

And they did take a beating. 1975 was also the year that Johnny Rotten would walk the streets of London in a shirt that read “I Hate Pink Floyd,” officially positioning their brand of immersive, meticulous world-building as the old guard against which this thrashing, youthful music raged. And while the woozy, noirish groove of “Have a Cigar” might have sounded to the punks no different from the industry gloss satirized in its lyrics, listening to it now reveals just how well this band’s sound has aged. Early on, they won over new audiences by improvising against dazzling light shows. By this point, they knew how to turn each song into its own visual world: so intricate, so evocative, and so singular in its texture that you could never confuse it for any other band.

This skill led to Wish You Were Here becoming Pink Floyd’s most cohesive record: a dark, enveloping mood piece from a band that often aimed to provide escape. Some critics missed the old sound. They argued that it felt slight—just three songs sandwiched between the two sweeping movements of “Shine On You Crazy Diamond.” Others argued that its tone of defeat was too persuasive to feel artful. “If your use of the machinery isn’t alive enough to transcend its solemn hum—even if that hum is your subject—then you’re automatically trapped,” wrote Ben Edmonds for Rolling Stone. And then there’s Genesis, who, still enraptured with the vision of progressive rock as something that could grow in opposition to the monolithic forces of popular music, listened and wondered where that old ambition went.

The irony is that Waters’ theory would soon be tested and proven correct. Not only would Genesis abandon their prog roots to make mainstream rock for the masses, but their lineup also spawned a solo pop career—a feat that even Pink Floyd could never manage. Despite the creative and commercial highs in the decades that followed, being in this band could sometimes look like a demanding and high-paying desk job from which you could never quite retire: one filled with intrapersonal feuds, corporate sponsorships, and depressing compromises. As recently as this month, Gilmour confessed to feeling “bullied” into releasing what was billed as the “final” Pink Floyd album back in 2014: a meager, mostly instrumental collection called The Endless River that he wishes had been treated more like the fans-only curio it was. “But, you know,” he sighed, “it’s never too late to get caught in one of these traps again.”

And so, Wish You Were Here exists as a stark omen for the treacherous road ahead, a steely farewell to the simpler path behind. Nearly 50 years and 20 million in sales later, it’s safe to say this theme resonated far beyond the cloistered world of rock stardom. It didn’t replicate the culture-defining ubiquity of Dark Side nor the feature-length conceptual heft of 1979’s The Wall. But, fitting for a record born from growing pains and adult disillusionment, its legacy is somewhat more understated. There is an apocryphal legend that this is the album that convinced Gilmour to quit smoking, after he heard his unsuppressable cough somewhere low in the mix during the staticky intro of the title track. It also inspired one of the coolest packaging designs in music history, from the band’s loyal collaborator Storm Thorgerson at Hipgnosis, who talked the record company into selling the album with an opaque black sleeve so that serious collectors might own the album without ever actually seeing the real cover. (“Brilliant,” he says in a 2012 documentary, snapping his fingers at the camera: “That’s really absent!”)

But the most famous story about Wish You Were Here is a more troubling one. On a late spring day in June 1975, Barrett wandered into the recording studio, physically transformed, eyes vacant, unrecognizable to his former bandmates. Everyone present has retold the story the same way over the ensuing decades: No one could believe it was him. He had no response to the new music they played for him. He seemed to be in another world entirely. It was the last time most of the band saw him before his death in 2006. Gilmour has said he thinks about him every time he sings the title track, a staple of the band’s catalog that he’s since referred to as a “very simple country song.” Its imagery of a heaven indistinguishable from hell, of heroes traded for ghosts, have become so ingrained in our FM radio subconscious that it can be hard to remember how gutting it must have felt from this band who achieved everything they wanted and still found themselves haunted, hardened, beaten down by where their dreams had led them. After all, Wish You Were Here is what it says on postcards from somewhere beautiful. But it also means you’re alone.