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' 1966 US tour Today", released on 20 June 1966, were the most-recently released songs performed. "If I Needed Someone" was the most recent US released song (appearing on "Yesterday and Today" in June 1966) and "Paperback Writer" was the most recent US released single (released in May 1966) performed. The three remaining tracks performed from "Yesterday and Today" were previously released in 1965 and early 1966 as singles. The Beatles' 1966 US tour The Beatles staged their third concert tour of America in August 1966, and it was the last commercial tour they undertook. Lasting a total of 19 performances, with 17 shows