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>
The Beatles' Second Album of the original album sleeve containing the US mono and stereo mixes. In 2014, the album was released on CD again, individually and included in the Beatles boxed set "The U.S. Albums", which contained the album's running order but with UK mixes as remastered in 2009. The album was also issued on the EMI subsidiary label Odeon in 1964 for the Japanese market. That version had the same title and similar cover art but contained different songs than the US release. With the massive popularity of "Meet the Beatles!" and a desire for additional Beatles product as well as an