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>
With the Beatles years. The album became the first Beatles album released in North America when it was released in Canada on 25 November under the augmented title Beatlemania! With the Beatles, with additional text on the album cover, and issued only in mono at the time, catalogue number T 6051 (a stereo Canadian release would come in 1968, catalogue number ST 6051). "With the Beatles" was unevenly "split" over the group's first two Capitol albums in the United States; nine tracks were issued on "Meet the Beatles!" (the eight original compositions plus "Till There Was You"), and the remaining five, all "covers",