Rolling Stone:

Over the decades, many people have claimed to be the “fifth Beatle.” But the only person who can credibly hold that title was Martin. The producer not only signed the Beatles to their first record contract in 1962 but went on to work extensively with them on the vast majority of music they recorded over the next eight years, from “Love Me Do” to the majestic suite that wrapped up Abbey Road.

“George Martin made us what we were in the studio,” John Lennon said in 1971. “He helped us develop a language to talk to other musicians.”

And this fascinating bit:

Martin also played on some Beatles songs, including the piano on “In My Life.” “I couldn’t play the piano at the speed it needed to be played, the way I’d written the part,” he said in another 2012 interview. “I wasn’t that good a pianist, but if you had had a really good pianist, he could do it. I couldn’t get all the notes in. One night I was by myself and played the notes at half speed but an octave lower on the piano, recording at 15 inches per second. When I ran the tape back at 30 inches per second, the notes were at the right speed and in the correct octave.”

A tough loss.