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
Experimental pop as "[seeming] to have done it all". Martin wrote that, along with the Rolling Stones' "Their Satanic Majesties Request" (1967), the Beatles' "Sgt. Pepper" "opened a space" for experimental pop which would be later filled by Jimi Hendrix, Jethro Tull, and the Who's "Tommy" (1968). Prior to "Sgt. Pepper", Gary Usher and Curt Boettcher were Los Angeles-based songwriters and producers who were interested in classical music and the avant-garde. Later cited as fixtures of sunshine pop, they worked together to create their debut studio album, "Present Tense" (1968). It was credited to Sagittarius, a studio group referred to as an