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>
Yesterday (Beatles song) Yesterday (Beatles song) "Yesterday" is a song by the English rock band the Beatles, written by Paul McCartney (credited to Lennon–McCartney), and first released on the album "Help!" in the United Kingdom in August 1965. "Yesterday", with the B-side "Act Naturally", was released as a single in the United States in September 1965. While it topped the American chart in October the song also hit the British top 10 in a cover version by Matt Monro. The song also appeared on the UK EP "Yesterday" in March 1966 and the Beatles' US album "Yesterday and Today", released in June 1966.