Beatles Producer George Martin: '5th Beatle' Dead

George Martin, the incredibly brilliant producer of The Beatles who was such an influence on the group he was known as "the 5th Beatle" -- has died.

Martin passed away Wednesday at his home in London.

His influence cannot be understated. When Martin met the Beatles in 1962 he was not impressed ... he felt their music was all over the place, but, as he put it, "They were like plants in a hothouse. They grew incredibly fast."

Martin got initial resistance from John Lennon and Paul McCartney, who wrote the songs for the group, but they quickly grew to trust Martin like a partner. When they were recording "Yesterday," it was Martin who wanted to add a string quartet. Paul didn't get it at first, saying "We're a rock 'n' roll band!" Paul relented, and an empowered Martin added a cello and violin.

Martin's knowledge of technology was inspiration for the group ... best shown in songs like "Penny Lane," "Strawberry Fields Forever" and the crown jewel -- the album, "Sgt. Pepper's Lonely Hearts Club Band."

Paul called Martin "a second father," but all 4 guys revered him.