Lennon_McCartney Caricature 1965

Lennon & McCartney Caricature 1965; both shown here for a publicity photoshoot in London, with John Lennon age 25 and Paul McCartney, age 23.

The Lennon-McCartney songwriting partnership is one of the best known and most successful musical collaborations in history, with the Beatles selling over 600 million records, tapes and CDs as of 2004.

Unlike many songwriting partnerships that comprise separate lyricist and composer, both Lennon and McCartney wrote words and music. Sometimes, especially early on, they would collaborate extensively when writing songs, working “eyeball to eyeball” as Lennon put it.
By an agreement made before the Beatles became famous, when both were in their mid-teens, Lennon and McCartney were credited equally with songs that either one of them wrote while their partnership lasted.

When it came to songwriting, Author David Rowley points out that at least half of all Lennon–McCartney lyrics have the words “you” and/or “your” in the first line.

Lennon stated that “Paul provided a lightness, an optimism, while I would always go for the sadness, the discords, the bluesy notes”.
In some cases, two incomplete songs or song ideas that each had worked on individually would be combined into a complete song. Often one of the pair would add a middle eight or bridge section to the other’s verse and chorus. Producer George Martin attributed the high quality of their songwriting to the friendly rivalry between the two.

Lennon–McCartney, along with the Rolling Stones’ songwriting partnership between Mick Jagger and Keith Richards, as well as other British Invasion songwriters, inspired changes to the music industry because they were bands that wrote and performed their own music.

This new trend changed how rock and roll music was recorded in the USA; previous to The Beatles, most American band songs were recorded with session musicians, not by the band themselves.