Sgt. Pepper's Lonely Hearts Club Band is the eighth studio album by the English rock band the Beatles. Released on 26 May 1967,[nb 1] Sgt. Pepper is regarded by musicologists as an early concept album that advanced the roles of sound composition, extended form, psychedelic imagery, record sleeves, and the producer in popular music. The album had an immediate cross-generational impact and was associated with numerous touchstones of the era's youth culture, such as fashion, drugs, mysticism, and a sense of optimism and empowerment. Critics lauded the album for its innovations. The album's lyrics were printed in full on the back cover, the first time this had been done on a rock LP.[276] The record's inner sleeve featured artwork by the Dutch design team the Fool that eschewed for the first time the standard white paper in favour of an abstract pattern of waves of maroon, red, pink and white.[261][nb 23] Included as a bonus gift was a sheet of cardboard cut-outs designed by Blake and Haworth.