The music on the album is taken from the Incredible String Band's live mixed-media show of the same name, for which the band had just concluded performances when they recorded the album. The "U" show, which involved pantomime-like dancing along with music, had failed financially. Therefore, in an effort to recoup some of the losses, producer Joe Boyd booked the band for a mere two days in a recording studio to record what became a double album's worth of material. Despite the time constraints (literally 48 hours in which band members switched off in shifts between recording and napping) the album still contains (characteristically) rich overdubbing.
The letter "U" represented a transition from a high level of spiritual awareness to a low, then returning to a final peak of awareness and communication. The material on the album was meant as an expression of their understanding of Scientology practices and principles, as the band had recently converted to the religion.