Sgt. Pepper's Lonely Hearts Club Band album carried on the childhood and Liverpool theme with its circus and fairground effects, its pervading atmosphere of the traditional northern music hall that was in both its main creators' [McCartney and Lennon's] blood." "Sgt. Pepper" album cover was designed by the pop artists Peter Blake and Jann Haworth. Blake recalled of the concept: "I offered the idea that if they had just played a concert in the park, the cover could be a photograph of the group just after the concert with the crowd who had just watched the concert, watching them. If we did this by using cardboard
Concept album Moore says that "Even though previous albums had set a unified mood, it was on the basis of the influence of "Sgt. Pepper" that the penchant for the concept album was born." Adding to "Sgt. Pepper"s claim, the artwork reinforced its central theme by depicting the four Beatles in uniform as members of the Sgt. Pepper band, while the record omitted the gaps that usually separated album tracks. Author Bill Martin relates the assumed concept albums of the 1960s to progressive rock: "Popmatters" Sarah Zupko notes that while the Who's "Tommy" is "popularly thought of as the first rock opera,