The thesis is concerned with presenting different approaches to questions, mostly in logic and formal semantics. Initial definitions of the most important concepts, such as the difference between a question and an interrogative sentence, are followed by a historical overview of older approaches (in philosophy, generative grammar, and pragmatics) and a classification of recent ones. After that, the most important approaches, which, for the most part, take into account the answers to a question, are presented in more detail. These are alternative semantics (Hamblin: questions as sets of possible answers, Karttunen: questions as sets of true answers), partition semantics (questions as partitions of the logical space of possible worlds) and its dynamic version, and inquisitive semantics (different kinds of propositions are treated in an integrated way and a key new notion of issues raised by questions is further developed and formalized). The main focus is on direct polar and wh-questions. Finally, the treatment of entailment between questions in the presented approaches is summarized and some critical remarks are given. The whole analysis is supplemented by a short comparison of the approaches.