Pink Floyd’s enduring blockbuster merged grandeur and malaise. Very much a product of its era, it became one of the best-selling albums of all time.Glum, ponderous songs about madness, mortality and greed, punctuated with tense instrumentals. Was that a blueprint for a blockbuster? It hardly sounds like the makings of one of the best-selling albums of all time.But there’s no denying the popularity and tenacity of “The Dark Side of the Moon,” the indelible album that Pink Floyd released 50 years ago, on March 1, 1973. Looming like an inscrutable monolith, “Dark Side” spent nearly all of the next 14 years — through punk, disco, early hip-hop and the pop heyday of MTV — lodged in Billboard’s Top 200 album chart. It arrived during the analog, material days of record stores and vinyl LPs, when an album purchase was a commitment. And no matter how familiar “Dark Side” went on to become as an FM radio staple, people still wanted their own copy, or perhaps a new copy to replace a scratched-up one. In the digital era, “The Dark Side of the Moon” album returned to the charts on CD, selling and then streaming more millions.The success of “Dark Side” stoked the ambitions of Pink Floyd and its leader, Roger Waters, who has toured arenas and stadiums ever since; Waters, 79, is playing his “first ever farewell” dates this year. He conceived the “The Wall,” a narrative rock opera released in 1979, that would foreground his anti-authority reflexes, from schoolmasters to heads of state; he has performed it against the backdrop of the Berlin Wall. Decades later, Waters would go on to spout cranky, conspiracy-theory-minded, pro-Russia political statements that many former fans abhorred. When “Dark Side” appeared, all that was far in the future.There will, of course, be another deluxe edition for the latest “Dark Side” anniversary. Arriving March 24, the new boxed set has high-resolution and surround-sound remixes and other extras, though it’s largely redundant after the exhaustive “Immersion Edition” reissue in 2011. Both “Immersion” and the new set include a worthy 1974 concert performance of “Dark Side,” with brawny live sound and extended onstage jams.Waters has also announced his own full-length remake of “Dark Side,” that will have his own lead vocals — not the husky, doleful voice of Pink Floyd’s guitarist, David Gilmour — with Waters’s spoken words over the album’s instrumentals, along with “no rock ’n’ roll guitar solos.”Uh-oh.In 1973, “Dark Side” was an album that worked equally well to show off a new stereo — or, for a few early adopters, a quadraphonic system — or to be contemplated in private communion with headphones and a joint. The ticking clocks, alarms and chimes that open “Time” are startlingly realistic even when they’re no longer a surprise, and the perpetual-motion synthesizers and desperate footfalls of “On the Run” are eternally dizzying.Stately tempos, cavernous tones and solemn framing announce the high seriousness of “Dark Side,” which begins and ends with the sound of a heartbeat. The album juxtaposes overarching sonics and grand pronouncements with human-scale experience. Its tracks are punctuated with voices from Pink Floyd’s road crew and friends, dispensing loop-ready tidbits like “I’ve always been mad” in working-class accents.Like other overwhelming best sellers of the 1970s and 1980s — Michael Jackson’s “Thriller,” the Eagles’ “Hotel California,” Fleetwood Mac’s “Rumours” — “Dark Side” deals with disillusionment, fear and resentment despite the polish of its production. It’s troubled and obsessive at heart, not tidy. Countless bands and producers would learn from Pink Floyd how to fuse grandeur and malaise, how a few well-placed sounds can say far more than a showy display of virtuosity.“Dark Side” was very much a product of its era. The early 1970s were prog-rock’s heyday, particularly in Britain, where bands like Genesis, King Crimson and Yes were constructing suite-length songs and unveiling elaborate conceits. But the early 1970s were also a time when the utopian promises of the hippie era were fading, pushed back by entrenched interests and corporate co-optation. “Dark Side” captures naïve hopes falling away.It was Pink Floyd’s eighth album, the continuation of a cult career that had been synonymous with psychedelia and progressive rock: with extended structures and open-ended jams, with verbal conundrums and with an oh-wow appreciation of reverberant textures and spatial effects.Pink Floyd’s founding songwriter, Syd Barrett, left the band in 1968 with mental health problems, taking its sense of whimsy with him. Waters emerged as its new, more saturnine leader. But it took a string of uneven albums, full of amorphous studio jams, before the relative concision and clarity of “Dark Side” came into focus. While the album unfolds as a 42-minute prog-rock suite — despite the necessity, in 1973, of flipping over an LP — it also features clearly delineated verse-chorus-verse songs that radio stations could play. Waters deliberately made his lyrics blunter and more down-to-earth than he had before: “Money, it’s a gas/Grab that cash with both hands and make a stash.”Waters tackled big topics: “Time,” “Money,” war, the inevitability of death, the triviality of daily life, the importance of seizing the moment. His perspective is dour. In “Breathe (in the Air),” he describes life as a “race towards an early grave”; in “Time, he observes that every sunrise brings you “One day closer to death.” But the reason “Dark Side” became a blockbuster is that Pink Floyd’s music — the full band, with Richard Wright’s self-effacing but fundamental keyboards, Waters on bass, Nick Mason’s steadfast drumming and Gilmour’s probing, slashing, keening guitar — defies all that miserabilism.The album builds dramatically and inexorably toward the songs that close each side of the LP. “The Great Gig in the Sky,” which ends Side 1, is a progression of tolling, processional keyboard chords from Wright, topped by spoken words denying fear of death — “You’ve got to go sometime” — followed by Clare Torry’s leaping, soaring, riveting vocal improvisation. She’s a pure life force, with pain and freedom and determination in her voice, refusing to accept oblivion. (Torry only received composer credit for her top line in 2005, along with an undisclosed settlement, after suing the band.)The album’s conclusion — “Brain Damage” seguing into “Eclipse,” both written by Waters — reads as bleak but feels like transcendence. In “Brain Damage,” the singer feels himself succumbing to mental illness. “The lunatic is in my head,” he warns, answered by a snippet of maniacal laughter; in the chorus, he sings, “If your head explodes with dark forebodings too/I’ll see you on the dark side of the moon.”Then, in “Eclipse,” he makes his way toward a revelatory oneness — “All that is now and all that is gone/And all that’s to come and everything under the sun is in tune” — only to see it swallowed by darkness as “the sun is eclipsed by the moon.” But in both songs, the music swells behind him, with churchy organ and robust major chords, pealing guitar and gospelly choir harmonies. As the album ends, tidings of catastrophe sound like triumph; it’s a fist-pumping arena-rock finale.In recent interviews, Waters has described the message of the album more positively. “What is really important is the connection between us as human beings, the whole human community,” he told Berliner Zeitung in February. That’s revisionist; “Dark Side” luxuriates in alienation, futility and desperation. Its persistence reveals just how many listeners feel the same. More