Sampling
The Beatles first used samples of other music on "Yellow Submarine", the samples being added on 1 June 1966. The brass band solo was constructed from a Sousa march by George Martin and Geoff Emerick, the original solo was in the same key and was transferred to tape, cut into small segments and re-arranged to form a brief solo which was added to the song.
A similar technique was used for "Being for the Benefit of Mr. Kite" on 20 February 1967. To try to create the atmosphere of a circus, Martin first proposed the use of a calliope (a steam-driven organ). Such was the power of the Beatles within EMI that phone calls were made to see if a calliope could be hired and brought into the studio. However, only automatic calliopes, controlled by punched cards, were available, so other techniques had to be used. Martin came up with taking taped samples from several steam organ pieces, cutting them into short lengths, "throwing them in the air" and splicing them together. It took two trials; in the first attempt, the pieces coincidentally came back in more or less original order.
More obvious, and therefore more influential samples were used on "I Am the Walrus"—a live BBC Third Programme broadcast of King Lear was mixed into the track on 29 September 1967. McCartney has also described a lost opportunity of live sampling: the EMI studio was set up in such a way that the echo track from the echo chamber could be picked up in any of the control rooms. Paul Jones was recording in a studio whilst "I Am the Walrus" was being mixed and the Beatles were tempted to "nick" (steal) some of Jones's singing to put into the mix.
Read more about this topic: The Beatles' Recording Technology