Sgt. Pepper's Lonely Hearts Club Band is the eighth studio album by British rock band The Beatles. Released 1 June 1967, it became a defining album in the emerging psychedelic rock style; it has since been recognised by prominent critics and publications as one of the most influential albums of all time. Recorded over a 129-day period beginning in December 1966, Sgt. Pepper sees the band exploring further the experimentation of their previous album, 1966's Revolver. Making use of orchestras, hired musicians and innovative production techniques, the album incorporates elements of music hall, rock and roll, western classical- and traditional Indian music; its lyrics deal particularly with themes of childhood and everyday life. The album is loosely based on a concept that the Beatles are performing as the fictitious band of the album's title; the cover art, depicting the band posing in front of a montage of famous individuals, has itself been widely acclaimed and imitated.