Sgt. Pepper's Lonely Hearts Club Band "Being for the Benefit of Mr. Kite!" and "A Day in the Life". Producer George Martin and engineer Geoff Emerick helped realise the group's ideas by approaching the studio as an instrument, applying orchestral overdubs, sound effects and other methods of tape manipulation. Recording was completed on 21 April 1967. The cover, depicting the Beatles posing in front of a tableau of celebrities and historical figures, was designed by the British pop artists Peter Blake and Jann Haworth. "Sgt. Pepper" is regarded by musicologists as an early concept album that advanced the use of extended form in popular music while
Cultural impact of the Beatles as, in author Shawn Levy's description, "the world's first household psychedelics, avatars of something wilder and more revolutionary than anything pop culture had ever delivered before". Author Carys Wyn Jones locates "Sgt. Pepper's", along with "Pet Sounds", to the beginning of art rock. Both albums are largely viewed as beginnings in the progressive rock genre due to their lyrical unity, extended structure, complexity, eclecticism, experimentalism and influences derived from classical music forms. For several years following "Sgt. Pepper" release, straightforward rock and roll was supplanted by a growing interest in extended form. Several of the English psychedelic bands who followed