Nightcap : The Unrelease Masters 1972-1991 (1993) is a Jethro Tull double CD album released on 22 November 1993 with older and previously unreleased material. The first CD contains material recorded in August 1972, much of which would be re-recorded and re-arranged as their sixth album, A Passion Play (1973). (The lyrics to Critique Oblique and Scenario actually refer to "passion play".) The second CD ranges from 1974 to 1991. The album was produced in limited quantities with proceeds going to charity.