Revolver is the seventh studio album by the English rock band the Beatles. It was released on 5 August 1966, accompanied by the double A-side single "Eleanor Rigby" / "Yellow Submarine". The album was the Beatles' final recording project before their retirement as live performers and marked the group's most overt use of studio technology to date, building on the advances of their late 1965 release Rubber Soul. It has since become regarded as one of the greatest and most innovative albums in the history of popular music, with recognition centred on its range of musical styles, diverse sounds and lyrical content. The Beatles recorded Revolver after taking a three-month break at the start of 1966, and during a period when London was feted as the era's cultural capital. Regarded by some commentators as the start of the group's psychedelic period, the songs reflect their interest in the drug LSD, Eastern philosophy and the avant-garde while addressing themes such as death and transcendence of material concerns. With no plans to reproduce their new material in concert, the band made liberal use of automatic double tracking, varispeed, reversed tapes, close audio miking, and instruments outside of their standard live set-up. Among its tracks are "Tomorrow Never Knows", incorporating heavy Indian drone and a collage of tape loops; "Eleanor Rigby", a song about loneliness featuring a string octet as its only musical backing; and "Love You To", a foray into Hindustani classical music. The sessions also produced a non-album single, "Paperback Writer", backed with "Rain".