Abbey Road is the eleventh album by English rock band the Beatles, released on 26 September 1969 by Apple Records. The recording sessions for the album were the last in which all four Beatles participated. Although Let It Be was the final album that the Beatles completed before the band's dissolution in April 1970, most of the album had been recorded before the Abbey Road sessions began. A double A-side single from the album, "Something"/"Come

Side two contains a 16-minute medley of eight short songs, recorded over July and August and blended into a suite by McCartney and Martin. Some songs were written (and originally recorded in demo form) during sessions for the White Album and Get Back / Let It Be, which later appeared on Anthology 3. While the idea for the medley was McCartney's, Martin claims credit for some structure, adding he "wanted to get John and Paul to think more seriously about their music".  The first track recorded for the medley was the opening number, "You Never Give Me Your Money". McCartney has claimed that the band's dispute over Allen Klein and what McCartney viewed as Klein's empty promises were the inspiration for the song's lyrics. However, MacDonald doubts this given that the backing track, recorded on 6 May at Olympic Studios, predated the worst altercations between Klein and McCartney. The track is a suite of varying styles, ranging from a piano-led ballad at the start to arpeggiated guitars at the end. Both Harrison and Lennon provided guitar solos with Lennon playing the solos at the end of the track, which Beatles author Walter Everett considers his favourite Lennon guitar contribution.  This song transitions into Lennon's "Sun King" which, like "Because", showcases Lennon, McCartney and Harrison's triple-tracked harmonies. Following it are Lennon's "Mean Mr. Mustard" (written during the Beatles' 1968 trip to India) and "Polythene Pam". These in turn are followed by four McCartney songs, "She Came in Through the Bathroom Window" (written after a fan entered McCartney's residence via his bathroom window), "Golden Slumbers" (based on Thomas Dekker's 17th-century poem set to new music), "Carry That Weight" (reprising elements from "You Never Give Me Your Money", and featuring chorus vocals from all four Beatles), and closing with "The End".  "The End" features Starr's only drum solo in the Beatles' catalogue (the drums are mixed across two tracks in "true stereo", unlike most releases at that time where they were hard panned left or right). Fifty-four seconds into the song are 18 bars of lead guitar: the first two bars are played by McCartney, the second two by Harrison, and the third two by Lennon, with the sequence repeating. Harrison suggested the idea of a guitar solo in the track, Lennon decided they should trade solos and McCartney elected to go first. The solos were cut live against the existing backing track in one take. Immediately after Lennon's third and final solo, the piano chords of the final part of the song begin. The song ends with the memorable final line, "And in the end, the love you take is equal to the love you make". This section was taped separately to the first, and required the piano to be re-recorded by McCartney, which was done on 18 August. An alternative version of the song, with Harrison's lead guitar solo played against McCartney's (with Starr's drum solo heard in the background), appears on the Anthology 3 album and the 2012 digital-only compilation album Tomorrow Never Knows.

Using a quote from the above article, answer the following question: Who is Allen Klein?