"Written mostly by Paul McCartney and is credited to Lennon/McCartney. In March 1968 it was released as a single, backed by "the Inner Light".
The song was recorded at Abbey Road Studios during sessions on 3 February and 6 February 1968, before the Beatles left for India. This single was the last release by the band on Parlophone in the UK and Capitol Records in the U.S.. All subsequent releases, starting with "Hey Jude" in August 1968, were released on their own label Apple."
The song, and in particular, the intro, is similar to Humphrey Lyttelton's "Bad Penny Blues" from 1956. John Lennon helped write the lyrics. The line "see how they run" was included after his suggestion (and was a theme that had been used in the previous year's "I Am the Walrus".