Over the Moon

Hanging on 

in quiet desperation 

is the English way

Along with the ubiquity of fast food drive-throughs, questionable road surfaces and sparring with trucks large enough to have their own electorate, the essence of the American road trip lies in wading through the alphabet soup of radio stations that blanket the country.

As you cruise along at genteel, radar-enforced speeds, you dial through the stations like a master safe cracker, frantically trying not to get stuck on a frequency offering country music, hellfire-and-damnation religion, or whack jobs spewing forth on the right to use uranium-tipped bullets when hunting small animals.

Eventually in this megahertz miasma you will come across something as familiar as your own face, and indeed as old as your face. It will be a riff, a chorus or a solo. You have found a classic rock station.

We Brits may have developed an awkwardness towards our own musical legacy, but Americans positively embrace those who led the British invasion of the 1960s and 70s. The likes of Led Zeppelin, The Who, Cream, the Stones and even The Beatles are often considered their own, part of the fabric that built the modern American culture. It is no accident that Tony Soprano, that icon of the American dream, drove - and frequently crashed - to the sound of New York's WAXQ, being of the generation of Americans who hold due reverence for the music that defined the rock era.

In the UK, classic rock artists - while still celebrated (as we saw during last summer's Olympic entertainment) - have been consigned to darkening corners of the radio spectrum. Although Stairway To Heaven was never released as a single, the idea of playing it in daylight hours is akin to walking naked down Oxford Street playing the German national anthem on a kazoo - somewhere between unfashionable, eccentric and arrestable.

But find yourself within 100 miles of any American conurbation between sea and shining sea and you will never be more than 20 minutes away from a station playing a track from Rumours or Frampton Comes Alive. Or a track from one of the most revered albums ever made, one that continues to draw superlative regard as it enters its fifth decade, and which, this week, celebrates its 40th anniversary: Pink Floyd's Dark Side Of The Moon.

With more than 50 million copies in circulation in the world and a cover that even those who've never listened to the record will recognise, Dark Side Of The Moon was a landmark record, full of landmarks. Musically, it is the definitive Pink Floyd album (although the surviving Floyd members still dispute this - Roger Waters citing The Wall, David Gilmour favouring Wish You Were Here).

It is also as musically accessible as anything in the Floyd canon. Breathe, the album's first musical track, is seemingly built out of an extended bluesy jams that were the band's hallmark in their early days in London's underground club scene, the only notable shift being Richard Wright's Miles Davis-influenced chord changes on the piano.

In principle, however, DSOTM is a concept album, lyrically owing much to bassist and lead writer Roger Waters' perennial obsessions with distance, separation (the loss of Syd Barrett) and death (the loss of his father at Anzio during World War II), and a growing cynicism towards the modern world.

Not that Dark Side Of The Moon is so starkly contrived. Like so many albums of its time, it's as much a collection of happy accidents as a narrative of conscious statements on these topics: death is covered more or less melodically by The Great Gig In The Sky, with Clare Torry's lyric-free, lung-rattling one-take vocal (for which she received the princely fee of £30 - later successfully contested in court), built over Wright's mournful piano. Happy it may not be, but by its end, few listeners have ever been anything other than exhilarated by one of the most memorable vocal performance in music history.

Lyrically DSOTM engenders some reasonable criticism. Even Waters himself has described lines like those on Breathe as "a bit Lower Sixth" ('Breathe, breathe in the air. Don't be afraid to care. Leave, don't leave me. Look around and choose your own ground), but such lack of erudition can be easily glossed over by the mammoth impact of the album's music.

Like most episodes of Monty Python's Flying Circus, the social commentary of Money, is dating, especially if you regard new cars and caviar the height of extravagance. Still, as prescient as references to LearJets and buying football teams may have been, reflecting Waters' underlying socialist bent, they're hardly in the same league of rock star awkwardness as We Didn't Start The Fire or Sting singing about the plight of Russian children.

While Money afforded a generation of gauche adolescents the opportunity to let rip with the "goody-good bullshit" line, it also became the first Floyd song to be a commercial hit. One of the most unlikely aspects of this is one of the song's least obvious aspects - its obscure 7/4 time signature providing the 1-2-3-4-1-2-3 cyclical bass figure, a walking blues with its roots in Booker T & The MGs' Green Onions. And, of course, it features that looped sound effect of a cash register and the splash of coins being thrown by Waters into one of his wife's pottery creations, with the loop then spliced into seven pieces and hooked around upturned chair legs to keep with the 7/4 time.

Money isn't the album's only taste of sound effects, of course: the ticking and ringing alarm clocks of Time and the pulsing heartbeat that heralds the opening track, Speak To Me and the album's first words: "I've been mad for fucking years, absolutely years, been over the edge for yonks". This and other excerpts of spoken voice throughout the album was the result of Waters using cue cards to ask stock questions to various hangers-on around Abbey Road Studios including (but never used) Paul McCartney, road manager Peter Watts (father of actress Naomi) and the cheerful studio doorman Gerry O'Driscoll ("I'm not afraid of dying. Any time will do").

And there's the mournful Us and Them, a song loosely about depression (another Waters theme), and built on a Rick Wright composition originally written for the 1970 film Zabriskie Point by Italian director Michelangelo Antonioni (and featuring a brief appearance by Harrison Ford, trivia fans). In place of a traditional middle eight, it features roadie Roger 'The Hat' Manifold, airing his wisdom on a road rage perpetrator.

I mean, they're not gonna kill ya. If you give 'em a quick short, sharp, shock, they won't do it again. Dig it? I mean he got off lightly, 'cause I would've given him a thrashing - I only hit him once! It was only a difference of opinion, but really...I mean good manners don't cost nothing do they, eh?

Dark Side Of The Moon has been hailed greatly and derided selectively. To the punk movement it was a convenient target, hippies going mad amid a barrage of bloated excess and overwrought self-examination that famously remained on the Billboard Hot 100 for decades after its release. Along with Emerson & Palmer's invention of the behemoth stadium tour, DSOTM is frequently suggested as one of the seeds of punk. It isn't, and shouldn't, and in some respects Money even predicts the coke-shoveling, overblown state that rock music found itself in during the mid-1970s, giving punk a platform to rail against.

At just over 42 minutes' long - constrained, of course, by the capacity of vinyl - DSOTM is short by comparison with some of the opuses of the day. And while it may well, as Waters ascertains, been the beginning of the end for Pink Floyd (or at least the album on which the creative tensions between Waters and Gilmour began to turn more dysfunctional), it is still, 40 years on, a remarkable record.

On March 24, 1973, when Dark Side Of The Moon was released, the concept album wasn't anything new. Pet Sounds, Sgt. Pepper, even Who's Next had all attempted some sort of narrative, musical theatre of the mind. But unlike Waters' deliberately more theatrical effort with The Wall, DSOTM presents a more subtle collage, the central theme being modern life and how rubbish it really is.

Gloriously melancholy, in a way only an English songwriter could write. Perfect, then, for driving on American roads.