Revolver (Beatles album) group collective since 1962, and gave them an unprecedented amount of time to prepare for a new album. Writing in "The Beatles Forever", Nicholas Schaffner cites 1966 as the start of the band's "'psychedelic' period" and adds: "That adjective implies not only the influence of certain mind-altering chemicals, but also the freewheeling spectrum of wide-ranging colors that their new music seemed to evoke." Music journalist Carol Clerk describes "Revolver" as having been "decisively informed by acid", following John Lennon and George Harrison's continued experimentation with the drug LSD since the spring of 1965.<ref name="Clerk/Uncut"> Available at Rock's Backpages (subscription required).</ref>
1 (Beatles album) its original full-length version (slightly over seven minutes); on the American version of "20 Greatest Hits" it had been released as a shortened version. Before "1", all 27 songs were available mainly in two remastered CD versions. First on the respective Beatles albums released in 1987 (as well as "Past Masters, Volume One" and "Past Masters, Volume Two", released in 1988). The second remastering was made available on the CD versions for "1962–1966" and "1967–1970" (released in 1993). The songs on "1" were remastered specifically for the release in 2000. According to the liner notes of the album, the original