When Sleuth made its first appearance on the London stage in February 1970, it saw instant success. Moving to Broadway the following November, it won equal praise, even winning a Tony Award in 1971. In the program, audiences and reviewers were asked not to reveal the plot to anyone who had not yet seen the play, for so much of the enjoyment of the play was derived from its almost constant plot twists. Working on the idea of a whodunit, Shaffer instead created the first of its kind: a whodunwhat.

Part of the success of Sleuth comes from Shaffer's misappropriation of the mechanics of the classic murder mystery. More of the success derives from Shaffer's skill at scripting the play. It is filled with baroque language, exaggerated characters, and pompous intellectualism; yet its pretensions are consistently undercut with elements of the farcical, such as Milo's donning of the clown costume Another reason that audiences throughout the world have enjoyed it for years on end is that it is simply pure entertainment. Milo and Andrew match wits with the delicacy of cats inching around their prey. The audience is brought to points of both laughter and terror as the two men play, exchanging roles as cat and then as mouse, until their eventual downfall.