The Beatles (album) stereo only. In the UK, the following album, "Yellow Submarine", was the last to be shipped in mono. The mono version of "The Beatles" was made available worldwide on 9 September 2009, as part of "The Beatles in Mono" CD boxed set. A reissue of the original mono LP was released worldwide in September 2014. The album's sleeve was designed by pop artist Richard Hamilton, in collaboration with McCartney. Hamilton's design was in stark contrast to Peter Blake's vivid cover art for "Sgt. Pepper's Lonely Hearts Club Band", and consisted of a plain white sleeve. The band's name, in Helvetica,
Cultural impact of the Beatles as, in author Shawn Levy's description, "the world's first household psychedelics, avatars of something wilder and more revolutionary than anything pop culture had ever delivered before". Author Carys Wyn Jones locates "Sgt. Pepper's", along with "Pet Sounds", to the beginning of art rock. Both albums are largely viewed as beginnings in the progressive rock genre due to their lyrical unity, extended structure, complexity, eclecticism, experimentalism and influences derived from classical music forms. For several years following "Sgt. Pepper" release, straightforward rock and roll was supplanted by a growing interest in extended form. Several of the English psychedelic bands who followed