The Fifth Beatle. Every bit as influential in the development of their musical sound as the members themselves.
In searching for something to use as example, I came across this article, and really can’t articulate it any better.
He wrote the piano part for “In My Life”
Overseeing the tape loop on “Tomorrow Never Knows”
And a story about which I was unaware. Apparently, The Beatles recorded two different versions of “Strawberry Fields Forever”, John Lennon announced he wanted to use both versions. Problem was they weren’t in the same key, so one was a little shorter than the other. George Martin ended up changing the speed of both so they matched up. The result is one of The Beatles’ most iconic songs.