“The concept grew out of group discussions about the pressures of real life, like travel or money, but then Roger broadened it into a meditation on the causes of insanity,” recalls Nick Mason. As a concept album, Dark Side Of The Moon was pretty loose. The sonic experience of the album is as vivid now as it was then. You are now eight minutes into the album, and there’s another 35 to go. As it dies away there’s the reassuring tick of a clock which just has time to lull you again before a cacophony of alarm clocks shatters your senses and leads into the heavy ponderous guitar chimes of Time. It all ends in a dull explosion and more running footsteps. Just as you’ve relaxed into the song, however, it suddenly shifts gears and you are being carried long by a rapid hi-hat rhythm and electronic riff while atmospherics, voices, footsteps, airplanes and bits of feedback fly by on either side of your head. That in turn collides with a screaming female voice before subsiding into the slow, deliberate beat and soothing guitars of Breathe. You could lie back and hear the heartbeat gradually getting louder, mingled with a disembodied Scottish voice saying ‘I’ve been mad for fucking years’ and a maniacal laugh before being blotted out by a helicopter noise whirring from one ear to another. Dark Side… was the perfect stereo album and its pleasures were notably enhanced with the aid of a meticulously rolled Camberwell carrot. There was a rapidly expanding market for rock music for new generations, stereo had just become affordable and cannabis was becoming widely available. Released in March 1973, over a year after the band had previewed most of the tracks at London’s Rainbow Theatre, Dark Side Of The Moon caught the prevailing feeling perfectly. And like porn, men can go back to Dark Side Of The Moon over and over again. There’s certainly something in Roger’s theory, particularly if you accept (as most women do) that most men never get much further than puberty.