 The overview provided here of semantic theories of elementary questions is of course not exhaustive. There are a number of excellent recent handbook articles, each focusing on different aspects. Groenendijk and Stokhof (1997) provide a thorough review of the literature up to 1997, focusing on the partition theory, but also supplying an in-depth discussion of the epistemic-imperative approach (Åqvist 1965, Hintikka 1976, Hintikka 1983) and the treatment of questions in speech act theory (Searle 1969, Vanderveeken 1990).