Ian Leslie takes a fresh look at the Beatles in ‘John & Paul: A Love Story in Songs’

During the pandemic, Ian Leslie wrote a Substack essay called “64 Reasons to Celebrate Paul McCartney,” arguing that despite his accomplishments, the ex-Beatle was underrated. But he didn’t delve much into McCartney’s relationship with John Lennon, writing, “I’m trying to keep this essay-length and that subject, inexhaustibly fascinating, is a book in itself.”

Inspired by this, Leslie went and wrote that book: “John & Paul: A Love Story in Songs.” Despite a seemingly endless parade of Beatles books...