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
Sgt. Pepper's Lonely Hearts Club Band idea convincing to most ears." Author Martina Elicker similarly writes that, despite earlier examples, it was "Sgt. Pepper" that familiarised critics and listeners with the notion of a "concept and unified structure underlying a pop album", thus originating the term "concept album". Carys Wyn Jones locates "Pet Sounds" and "Sgt. Pepper" to the beginning of art rock; Julien considers the latter a "masterpiece of British psychedelia". According to historian David Simonelli, "Sgt. Pepper" established the standard for rock musicians, particularly British acts, to strive towards in their self-identification as artists rather than pop stars, whereby, as in the Romantic tradition,