Almost every time The Simpsons flashes back to Homer and Marge’s adolescence in the ‘70s, there is a poster hanging up on the wall of a prism with a beam of light shooting through it over a black background. No words adorn it. None need to. The picture, of course, is of the cover of Pink Floyd‘s Dark Side of the Moon, and as Matt Groening knows, it encapsulates its decade better than perhaps any other artifact pop culture has spit out since that term was coined. Like a handful of other albums which includes the Beatles’ Sgt. Pepper’s Lonely Hearts Club Band and Nirvana’s Nevermind, it is the one album that its entire genre agrees upon as the pinnacle of the form. No one did operatic space rock better than Pink Floyd did on Dark Side of the Moon, and it seems safe to say that no one ever will.

But just as Sgt. Pepper’s has received its share of barbs for its excesses (and just as Nevermind deserves to), Dark Side of the Moon is a punchline as often as not. Despite its record-setting tenure on the pop charts of about fourteen years straight and its continuing popularity, it is dated, not so much by music technology hitting the three-decade mark, but by the age at which its message strikes so forcefully. It’s been called the ultimate stoner’s album, but it’s really the ultimate alienated teen album. Some stalwart fans carry the torch for Dark Side far past the age at which they should drop it, but most rock fans of decent intelligence and sensitivity at least pass through a period of discovering and loving this record. Snobs of all stripes scoff at it, but there are plenty of reasons why the Floyd’s masterpiece has such longevity, and plenty of reasons why it deserves the in-depth look that the Classic Albums documentary series now gives it.

Featuring interviews with all the members of the band at the time as well as engineer Alan Parsons, mixing supervisor Chris Thomas, Rolling Stone editor David Fricke, and assorted others, Classic Albums gives Dark Side of the Moon the respect it deserves without tumbling over into uncritical worship. It doesn’t dish out the dirt on the earthly problems that felled this space rock behemoth ten years afterwards, mentioning only in passing the emptiness that creeps into a band once it has attained all its goals and the sticky mixing disagreements between Roger Waters and David Gilmour that would balloon with successive albums. Instead, it details the bits and pieces that coalesced to become one of the biggest records of all time, from a handful of coins dropping into a pottery mixing bowl to a chord that keyboardist Rick Wright lifted from Miles Davis’ Kind of Blue. The approach suits the band marvelously. As brief live clips remind us, the group’s stage presence was not based on any wild gyrations or sex appeal but on their complete immersion in their musical tools. It’s not for everyone, certainly, but for a cerebral rock fan, few thrills are bigger than watching Gilmour, Wright, or Waters bent in intense concentration over their instruments, coaxing their ethereal magic. The documentary understands this strength and delivers it in heaps. Segments of the gray and wrinkled band members recreating their individual parts are treats, but better still are the shots of Alan Parsons presenting the tracks for each song one at a time, adding and removing the effects, and at one point, recreating the famous introductory tape loop for “Money” by pulling the tape away from the machine and wrapping it around a microphone stand several feet to the side.

This last image, in its own offhand way, may just capture the spirit of Pink Floyd better than even their immortal album cover. Known in their time as cutting edge technologists, Pink Floyd’s innovations are reproduced in the digital age with relative ease, but even the fanciest gadget doesn’t make great music on its own. The documentary shows the machines employed for Dark Side, but it doesn’t share the assumption adopted by far too many of us moderns that dazzling technology can replace real musical substance. The creativity that it takes to use seven evenly-cut stretches of tape wrapped around a pole to make the rhythm track to a hit single in 7/8 time should be celebrated in any era. Even as the equipment used to create Dark Side of the Moon grows more and more primitive in relation to the present day, the record’s true merits live on. Fricke points out Pink Floyd’s deceptive simplicity, an unsung quality which has surely helped them avoid a spot in history’s dustbin next to Rick Wakeman, but it is the half-eloquent, half-incoherent Waters who says it best: Dark Side of the Moon is based on timeless, universal human emotions. The question of the album, according to him, is whether mankind is capable of being humane. Its concerns continue to be of deep interest to the thoughtful members of the human race, and if the album represents the melodramatic teenage discovery of those concerns more than a mature consideration of them, it still does so better than much of anything else in rock, and that’s an accomplishment well worth this documentary’s salute.