John Lennon and The Beatles’ music is teaming with hopeless romantic tropes. “Girl,” “Here, There and Everywhere,” “Something,” and “In My Life” are just a few of the notable ones that come to mind.

Together, the Beatles wrote some of the world’s most enduring love songs. John Lennon’s love letters, on the other hand, reveal a different, earthier type of poetry — and take a swipe at Paul ...