"Don't Let Me Down" was one of the Beatles' most powerful love songs, used for the B-side of "Get Back," and fairly popular on its own merit, reaching the Top 40 under its own steam. The principal composer for this outing was lead singer John Lennon, who delivered one of his most soulful vocals ever for the track: a vocal that conveyed soulful ecstasy and desperation. As with other of Lennon's songs from the late '60s, "Don't Let Me Down" manages to harmoniously string together what sound like fragments that could have developed into two or three different songs. The tune's mainstay is its chorus, with its rich wailing harmonies, consisting of nothing but the title. The verses usually extol the delightful infatuation of a fresh romance, motivated by the initiation of Lennon's long relationship with his soon-to-be-wife Yoko Ono. However, there's also a verse that goes into a different melody and peppier rhythm. Despite its assertions that the narrator is in love for the first time with a love that will last forever, there's a slight underlying feeling of anxiety and uncertainty, as if the singer suspects it might be too good to be true. As on "Get Back" and some other songs from the group's early-1969 Let It Be sessions, its soulfulness is accented by the electric keyboards of a temporary fifth Beatle, Billy Preston.