Caryl Lesley Churchill is a British playwright known for dramatising the abuses of power, for her use of non-naturalistic techniques, and for her exploration of sexual politics and feminist themes. Celebrated for works such as Cloud 9 (1979), Top Girls (1982), Serious Money (1987), Blue Heart (1997), Far Away (2000), and A Number (2002), she has been described as "one of Britain's greatest poets and innovators for the contemporary stage". In a 2011 dramatists' poll by The Village Voice, five out of the 20 polled writers listed Churchill as the greatest living playwright.

Cloud Nine is a 1979 British two-act play written by British playwright Caryl Churchill. It was workshopped with the Joint Stock Theatre Company in late 1978 and premiered at Dartington College of Arts, Devon, on 14 February 1979.