It’s not hard to argue the huge influence John, Paul, George and Ringo has had on popular music. But many overlook the huge contribution of their long time producer George Martin.
He was the first music industry professional to recognize the talent of the Beatles and get them signed to a label.
He was responsible for the Beatles beginning to branch out beyond guitar bass and drums arrangements
He introduced the Beatles to studio effects and tricks, many of which he developed.
There was no other external force more involved with the bands creativity and he came by the title “Fifth Beatle” honestly!