Bookends is the fourth studio album by Simon & Garfunkel. Produced by Paul Simon, Roy Halee and Art Garfunkel, the album was released on April 3, 1968, in the United States by Columbia Records. The duo had risen to fame two years prior with the albums Sounds of Silence and Parsley, Sage, Rosemary and Thyme and the soundtrack album for the 1967 film The Graduate. Bookends is a concept album that explores a life journey from childhood to old age. Side one of the album marks successive stages in life, the theme serving as bookends to the life cycle. Side two largely consists of unused material for The Graduate soundtrack. Simon's lyrics concern youth, disillusionment, relationships, old age, and mortality. Much of the material was crafted alongside producer John Simon, who joined the recording when Paul Simon suffered from writer's block. The album was recorded gradually over the period of a year, with production speeding up around the later months of 1967.