Among musicologists, Allan Moore says that "Sgt. Pepper" is composed mainly of rock and pop music, while Michael Hannan and Naphtali Wagner both see it as an album of various genres; Hannan says it features "a broad variety of musical and theatrical genres". According to Hannan and Wagner, the music incorporates the stylistic influences of rock and roll, vaudeville, big band, piano jazz, blues, chamber, circus, music hall, avant-garde, and Western and Indian classical music. Wagner feels the album's music reconciles the "diametrically opposed aesthetic ideals" of classical and psychedelia, achieving a "psycheclassical synthesis" of the two forms. Musicologist John Covach describes "Sgt. Pepper" as "proto-progressive".