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,
Experimental pop experimental pop groups. According to "The New York Times", Barrett and his subsequent solo albums "became a touchstone for experimental pop musicians". By the late 1960s, highly experimental pop music, or sounds that expanded the idea of the typical popular song, was positively received by young audiences, which cultural essayist Gerald Lyn Early credits to bands like Cream, Traffic, Blood, Sweat & Tears, and "of course", the Beatles. Drummer John Densmore believed that the Doors were on the cutting-edge of experimental pop music until he listened to the Beatles' album "Sgt. Pepper's Lonely Hearts Club Band" (1967), which he described