Obscured by Clouds
As the collection was meant to showcase the best of Pink Floyd, the decision was made to not include the soundtrack albums "More" or "Obscured by Clouds", or the albums "Ummagumma", "Atom Heart Mother" and "The Final Cut". The band's first album, "The Piper at the Gates of Dawn", was also omitted, as EMI were planning to release a special edition of the album at the time, and it was hoped that new fans would buy both this set and the re-released debut album.