My interest in The Dark Side Of The Moon dates back to an afternoon in 1993, when a commissioning editor at the New Musical Express handed me an advance copy of its 20th Anniversary Edition. “Can you review this?” he asked – and instantly, I could feel a second-hand punk-rock hostility welling in my bones.

Still, I thought I’d take the CD off his hands and, in the manner of the average 23 year-old music critic, rip it to pieces. I liked the unhinged, psychedelic side of Pink Floyd that had died with the departure of their drug-ruined founded Syd Barrett; what had followed his exit, I was sure, was some of the most indulgent, overcooked music ever put to tape.

This was, of course, the opinion of an ignoramus, who had paid far too much attention to the opinions of Joe Strummer, Johnny Rotten et al.

When I actually listened to Dark Side, I found a graceful, eloquent, beautifully-executed treatise on the human condition, whose songs numbered among the most wonderfully mood-altering stuff I had ever heard.

And so my mind was changed, and I belatedly investigated such records as Meddle, Atom Heart Mother, and Wish You Were Here (I still find The Wall very tough going, mind you).

In 2003, I got another Floyd-related commission from Rolling Stone magazine. This time, Dark Side had reached its thirtieth birthday – so there was yet another reissue, and more words to write. Better still, I now had the opportunity to interview its two chief architects, Roger Waters and David Gilmour, and divine the human story that lay beneath the music.

To say that the conversations that ensued were interesting is a howling understatement: when they shone light on their long-dead creative relationship, I could discern the same fascinating outlines that had defined Lennon Vs McCartney, Jagger Vs Richards et al: heart meeting head, art clashing with commerce, words battling with music.

I made a mental note to pursue the story – and when, a couple of months later, Da Capo called with a proposal for a Dark Side book, I said yes pretty much straight away.

I then spent a year or so putting together a story laden with musical and personal intrigue – and then watched, dumbfounded, as it dovetailed into the perfect coda: the massively unlikely Waters/Gilmour reunion at this summer’s Live 8 show.

As with all the best true stories, you couldn’t make it up.

— John Harris, October 10, 2005