A few of the songs made references to drugs, particularly John Lennon's songs. "She Said She Said" was about a party in Los Angeles the Beatles had gone to, and had taken LSD. "Doctor Robert" was about a New York doctor (Charles Roberts) who sedatives and "feel-good" drugs for his patients. "Tomorrow Never Knows" came from Lennon's reading "The Psychedelic Experience", which adapted the "Tibetan Book of the Dead" as a drug-user's guide.