John Lennon and Paul McCartney started writing songs together in the late 1950s and by 1963 were prolific composers. Continue
There were primarily three categories of Beatle Songs that were written but not released by the Beatles:
Recordings by the Beatles that the group tried but ultimately decided not to release.
Lennon–McCartney songs that the Beatles deemed unsuitable for the group at the outset and did not even attempt to record themselves.