By the time Pink Floyd released their ninth studio album, Wish You Were Here, in the fall of 1975, only eight years had passed since their debut. But in many ways, the five-track suite suggested a band that had endured far more than a decade of turmoil and triumph and, against expectations, thrived in the face of it. In the early days of their ascent, they’d lost Syd Barrett, the madcap leader whose fragile mental state quickly withered beneath the spotlight. And with 1973’s Dark Side of the Moon, Pink Floyd had become such commercial juggernauts that some of their most audacious peers, including Genesis, wondered if they could ever again construct the kind of cosmic wonders that had once flowed from Barrett’s brain. A moving memorial to their lost brotherhood with Barrett, Wish You Were Here doubles as a melancholic yes and a moving masterwork of mainstream rock introspection. Earlier that year, after Pink Floyd had already taken their new songs on tour in the States, Barrett famously dropped in on his old mates at Abbey Road. With his head shaved, his eyes distant, and his frame wide, Barrett first went unrecognized by the band. When Roger Waters ultimately played him “Shine On You Crazy Diamond”—the 25-minute psychedelic fantasy that went on to bookend the album—Barrett barely responded. But the song and record were about him, or, more broadly, the way the world and especially fame can dull the glow of someone who once “shone like the sun.” His visit reaffirmed the album’s bittersweet gist. Wish You Were Here famously has just five tracks, but each offers an entire universe of feeling, again belying a band that was still so young. Sung by Roy Harper, “Have a Cigar” is an unflinching account of music industry cynicism, the band riding a cool electronic strut to scorn the business’s shameless artistic exploitation. And the title track has become an ageless lament of joyous days that will never return, a country-western standard rendered by Englishmen so curious about audio frontiers they sampled the radio static of David Gilmour’s BMW in the parking lot for the intro. “We’re just two lost souls swimming in a fishbowl, year after year,” Gilmour sings at the climax, a line that so perfectly encapsulates the grind of whatever life you may lead that it has become one of music’s great slogans, as familiar as The Beatles or Shakespeare. Wish You Were Here is perhaps the saddest love letter any major band has ever sent itself—about what was, what is, and, tragically, what could never be. For the album’s 50th anniversary, Pink Floyd unlocked the vaults to find a “Wish You Were Here” take with jazz violin great Stéphane Grappelli, Waters’ demos of “Welcome to the Machine,” and an expansive instrumental version of “Shine On You Crazy Diamond.” But the real diamond is an April 1975 tape from the Los Angeles Memorial Sports Arena, captured by legendarily surreptitious taper Mike Millard. In this delightfully crisp recording, sonically upgraded from its decades as a bootleg favorite, the band wrestles with the emotional and musical heft of this new material and sounds monstrous in the process.