Suffice it to say, the making ofwas a time of uneasiness for Pink Floyd.

Tasked with making the follow-up to their landmark Dark Side of the Moon album (one of the best-selling records of all time), bassist Roger Waters, guitarist David Gilmour, drummer Nick Mason and keyboardist Rick Wright certainly weren't in the mindset where they could be super productive in the studio and write another Dark Side.

In fact they were struggling to come to terms with what they were doing, now that they'd made millions and ascended to among the biggest rock stars on the planet.

"In this post Dark Side of the Moon period, we were all having to assess what we were in this business for, why we were doing it and whether we were artists or business people," said Gilmour in the documentary The Story of Wish You Were Here. "Having achieved the sort of success and money out of all of that could fulfill anyone's wildest teenage dreams, why we would still want to continue to do it?"

Indeed, Waters has publicly stated that Pink Floyd was, for all intents and purposes, finished after Dark Side, in that there was nothing left to strive for as a band.

"We could have easily split up." - Roger Waters

Waters notes the band in 1975 was "at a watershed then and we could have easily split up, but we didn't because we were frightened of the great out there beyond the umbrella of this extraordinarily powerful and valuable trade name: Pink Floyd".

So with all these misgivings, the members began working at Abbey Road studios in January, 1975, setting about creating a new album, which would get released in September that year and go on to sell millions of copies.

However, it was a painfully slow grind plagued with infighting, particularly between Waters and Gilmour, as they struggled to come to terms with what the album should be and make new music to fit that vision.

Interestingly, the entire album got a kick start from those four, slow guitar notes that Gilmour strummed one day, which became the basis for "Shine On You Crazy Diamond". It was actually a song they had worked on before hitting the studio.

As their studio time got eaten up with nothing to show for it, Waters proposed taking "Shine On" and bookending the album with it, ultimately making it a nine-part track that was 26 minutes long.

Waters also wanted to axe two other songs they'd worked on in 1974 (which turned out to be "Sheep" and "Dogs" which appeared on Animals) in favour of writing new material. But Gilmour was adamantly opposed, wanting to use those two tracks along with "Shine On". This led to a huge fight between the two bandmates, with Waters ultimately winning the day.

"It felt cobbled to me. I didn't feel real," said Waters. "So at some point in the process, I came up with the idea that it has to be thematic.

Two Themes Emerge: Absence & Disillusionment

Two themes would emerge: Absence and the band's growing disillusionment with the record industry.

Waters came up with "Have a Cigar" and "Welcome to the Machine", two songs attacking the music business and it's eternal quest for the next big hit so record companies can fill their coffers off the backs of their recording artists - throwing them into the money-making machine.

For "Have A Cigar", neither Waters nor Gilmour could lay down a vocal that they thought suited the tone of song. They even tried singing it together, to no avail.

So they enlisted Roy Harper to handle vocals on that song, as he was working down in another Abbey Road studio.

And Harper nailed the tone of the lyrics as a greedy record exec who knows nothing about the artists working for him and only seeks to make more cash for the company.

"Everybody thought it was Roger," said Harper in the Wish You Were Here documentary. "I was a bit peed off at that."

Shine On You Crazy Diamond: An Ode to Syd Barrett

"Shine On You Crazy Diamond" is all about Syd Barrett, one of Floyd's founding members who was let go in 1968 because of his erratic behavior and apparent schizophrenia.

"He was kind of a crazy diamond and all of the things (the song) says about him in those brilliant lines are very, very accurate," said Gilmour, who replaced Barrett. "'You wore out your welcome with random precision' was certainly a part of him."

Waters wanted it to be a song "to get as close as possible to what I felt ... that sort of indefinable, inevitable melancholy about the disappearance of Syd."

Wright plays a brilliant keyboard piece as a tribute to Barrett that closes out the last 3:20 of "Shine On" (which is Part IX).

Shockingly for the four members of Pink Floyd, Barrett actually showed up in the studio on June 5, 1975, as they were working on the final mix for "Shine On". But he wasn't the elegant, wasted rock star they'd seen seven year earlier. Barrett was bald and very overweight, so nobody recognized him as he stood in the control room.

"How remarkable, how long it was before anyone actually woke up," said Gilmour, who was the first to recognize the man as Syd Barrett during those extremely awkward minutes. "And then we were all unbelievably shocked at his appearance. (He'd) turned rather balloon shaped, had no eyebrows and little hair."

Storm Thorgerson, who did the covers for Wish You Were Here and Dark Side of the Moon, noted that both Waters and Gilmour cried when they finally recognized Barrett.

Absence in Wish You Were Here

The song "Wish You Were Here" isn't so much about Barrett as it is about Waters thinking about absence. The song got its initial seed from Gilmour playing the opening riff, and when Waters heard it, he loved it. Both Waters and Gilmour wrote the chords for the rest of the song, with Waters penning the amazing lyrics.

"That collaboration between David and I is really good," said Waters. "It's a much more universal expression of my feelings about absence. Because I felt that we weren't really there. We were very absent."

Gilmour says "Wish You Were Here" does remind him of the man he replaced.

"'Wish You Were Here' has a broader remit. I can't sing it without thinking about Syd," said Gilmour. "Because of the resonance and the emotional weight it carries, it is one of our best songs."

Check out our look at why The Final Cut is one of Pink Floyd's best albums