Simon & Garfunkel's fourth studio album, "Bookends", was recorded in fits and starts from late 1966 to early 1968. Although the album had long been planned, work did not begin in earnest until late 1967. The duo were signed under an older contract that specified the label pay for sessions, and Simon & Garfunkel took advantage of this, hiring viola and brass players and percussionists. The record's brevity reflects its concise and perfectionist production; the team spent over 50 hours recording "Punky's Dilemma", for example, and rerecorded vocal parts, sometimes note by note, until they were satisfied. Garfunkel's songs and voice took a lead role on some of the songs, and the harmonies for which the duo was known gradually disappeared. For Simon, "Bookends" represented the end of the collaboration and became an early indicator of his intentions to go solo.