Pink Floyd were the prog-rock band whose psychedelic heart was ripped out when the mind of its enigmatic leader Syd Barrett began disintegrating.
Ironically, it was overuse of psychotropic drugs which was blamed for Barrett's descent into a mental black hole.
The substances Barrett used to inspire early Pink Floyd albums such as The Piper at the Gates of Dawn (1967) and A Saucerful of Secrets (1968) are thought to have triggered changes which meant he would never be the same again.
But it was after the fall of Syd Barrett that Pink Floyd came up with what many believe to be the greatest album of all time, Dark Side of the Moon.
The classic 1973 album, with its distinctive refracting prism artwork (by Storm Thorgeson) was shot through with early '70s angst and darkened still further by the theme of mental illness.
Guilt and concern over Barrett, who was 'eased out' of the band because of his bizarre behaviour, was hanging heavy over remaining Pink Floyd men Roger Waters, Rick Wright and Nick Mason.
The three brought in brilliant guitarist Dave Gilmour to replace Barrett.
And Gilmour's guitar work is one of the driving forces of Dark Side of the Moon, which opens with an eerie drum heart beat which echoes through the album.
Tracks such as Time, the cynical Money, Breathe and The Great Gig in the Sky, featuring a virtuoso vocal performance from Clare Torry, took the music world by storm. Dark Side of the Moon would stay in the top 100 for an incredible 11 consecutive years.
The album's phenomenal success made a lot of Lear jets and mansions for the Pink Floyd, who were still wracked with remorse over their wayward former band mate.
Wish You Were Here, the 1975 follow up to Dark Side of the Moon contains the track Shine on You Crazy Diamond, which is widely thought to be a direct reference to Syd Barrett.
Roger Keith Barrett (later nicknamed Syd) was born in Cambridge in 1946.
Together with Waters, Mason and Wright they formed bands called the T-set, Sigma 6, Meggadeaths and the Screaming Abbdabbs, then later the Pink Floyd Sound, then The Pink Floyd and lastly, Pink Floyd. …