On September 16 1968, work began at EMI Studio2 to complete a basic track for a new Paul McCartney composition entitled "I Will". It was also known very briefly as "Ballad". The song was written earlier in the Spring while The Beatles were in India. Paul plays acoustic guitar while John and Ringo play various percussion instruments.
You can hear take 1 with an edit of takes 34 and 35 of the song commercially released on the Apple 3-LP/2-CD "Anthology 3" project. This version is great with the exception of a few lyric changes. Also interesting is Paul's improvisations during these sessions. During take 19, for example, one of the improvisations include the snippet of "Can You Take Me Back" which would wind up on the new LP as a fragment before "Revolution 9".
The band is in an improvisational mood as well during take 30 and you can hear Paul singing a tune about the city of Havana for what is now entitled "Down In Havana".
During takes 34 to 36, you can hear Paul covering one of his recent compositions, a tune written for Cilla Black entitled "Step Inside Love" and eventually into another improvisation entitled "Los Paranoias" which is probably an inside joke as the band utilizes their percussion/acoustic guitar instrumentation to full use including a somewhat samba beat. Finally, during take 36 you can hear Paul covering the song "The Way You Look Tonight" somewhat mixed in with an attempt at "I Will".
The take selected for the commercial release was take 65, taken from a four track machine and copied to an eight track machine and re-named take 68.
The following evening on September 17 1968, Paul overdubbed another acoustic guitar, a second vocal, a mouthed bass and maracas. The song was mixed for mono on September 26 1968 and stereo on October 14 1968. The mono mix has the mouthed bass starting later in the song than the stereo mix.
The outtakes/ improvisations can be heard on various bootlegs including the CD versions of "Turn Me On Dead Man", "The John Barrett Tapes","Down In Havana" and "Mythology Volume 3",