In the nine years the Beatles were together, their music changed as they did, as the times did, as the world did. But through all the jumps in their sound, there were five common grounds: Lennon, McCartney, Harrison, Starr and the real fifth Beatle, George Martin.

From “Love Me Do” to “Let It Be,” it was Martin at the baton, arranging the music, producing the recordings, helping make John and Paul’s musical inventions and dreams come true and, when the four young men began to take the reins in the studio, knowing enough – well, to let them be.