An attempt to apply the principles of a theory of linguistic pragmatics which unites studies of presupposition, implicatures and speech acts (see J. Verschueren 1978: 'Reflections on presupposition failure') to present an analysis of Anthony Shaffer's play 'Sleuth'. The application is intended both as a test case for the theory, and as an attempt to illustrate the dynamic nature of texts, or text acts.