On June 01 1964, The Beatles gathered at EMI Studio 2 in order to continue recording the soundtrack album to the first film and the third official EMI LP : "A Hard Day's Night". The last song on the UK LP and the last song on the US LP: "Beatles '65" was the song entitled "I'll Be Back".
"I'll Be Back" was mainly written by John Lennon with the middle eight probably assisted by Paul. John is the main vocal although the song is sung in parts as a duet between John and Paul.
There are two takes of the song available commercially on the Apple 3-LP/2-CD "Anthology 1" album. These are takes 2 and 3. Both of the takes are mono. Take 2 is an attempt to play the song in 3/4 time (like a waltz) but it seems that the tempo sounds and feels awkward and the song is then changed to the regular 4/4 time. There is another attempt as take 3 but John seems to have problems with the phrasing of the lyrics as he sings them.
There are also some some very short snippets of the session (takes 12, 13, 14 and 15) also available commercially from the "Anthology" DVD series. These mainly consist of count-ins and breakdowns.