Strawberry Fields Forever
Since the Beatles usually did not include songs released as singles on their albums, both "Penny Lane" and "Strawberry Fields Forever" were left off "Sgt. Pepper's Lonely Hearts Club Band". With their omission, the Liverpool childhood theme that had been a loose concept behind the album was abandoned. Courrier describes the single as "a conceptual 45 if ever there was one". Martin came to regret the decision to omit the two songs, describing it as "the biggest mistake of my professional life". Against the Beatles' wishes, "Penny Lane" and "Strawberry Fields Forever" were included on the US "Magical Mystery Tour" album in November 1967. In 2017, both songs were included on the two-disc and six-disc 50th-anniversary editions of "Sgt. Pepper".