This song, which was begun in 1969 and can be heard in the Beatles' Let It Be sessions, was inspired by the book of the same name by Robert Masters and Jean Houston (1972), which emphasized the power of the human brain to induce various states of consciousness without the aid of external substances. The book presented a series of exercises intended to maximize one's potential for problem solving, conflict resolution, visionary thinking, creativity, focused listening and super-communication. Each application would start with a brief meditation cycle followed by the guided instructions of a director. During the exercise, only the director would speak, but each person would share their experience afterwards. Mind alteration had long since been a point of interest to Lennon, however he was aware of the risks involved with chemical consumption. A recommendation by Lennon himself is included with the book. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.