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 record, unique, clever, and stunning". In "The Times", William Mann described "Sgt. Pepper" as a "pop music master-class" and wrote admiringly of its use of "vivid" bass lines that partly recalled the Alberti tradition in classical music. He also commented that, so considerable were the album's musical advances, "the only track that would have been conceivable in pop songs five years ago" was "With a Little Help from My Friends". Having been among the first British critics to fully appreciate "Revolver", Peter Clayton of "Gramophone" magazine said that the new album was "like nearly everything the Beatles do, bizarre, wonderful,