When Paul McCartney looked back at his work in The Beatles, “And I Love Her” stood out to him as a milestone. At that point (early 1964), Paul hadn’t yet earned his reputation as a brilliant balladeer. That started to change after he wrote “And I Love Her.”
“It was the first ballad I impressed myself with,” Paul said in his biography Many Years From Now (1997). And John Lennon agreed with him. Thinking back on their rise as songwriters, John described Paul’s Hard Day’s Night gem as a warmup for “Yesterday.”
While John and Paul collaborated on many songs in those days, John had only minimal involvement in the writing of “And I Love Her.” (He probably helped with the middle section.) But Paul definitely hadn’t completed the track when he brought it into the studio.