Sir George Henry Martin was an English record producer, arranger, composer, conductor, and musician. He was commonly referred to as the "fifth Beatle" due to his extensive involvement in each of the Beatles' original albums. Martin's formal musical expertise and interest in novel recording practices facilitated the group's rudimentary musical education and desire for new musical sounds to record. Most of their orchestral and string arrangements were written by Martin, and he played the piano or keyboards on a number of their records. Their collaborations resulted in popular, highly acclaimed records with innovative sounds, such as the 1967 album Sgt. Pepper's Lonely Hearts Club Band.