The Logic of Interrogation (classical version) Jeroen Groenendijk Abstract: In this paper, we investigate the prospects of basing logic on cooperative information exchange instead of valid reasoning. To this end, we introduce a simple dialogue game of interrogation. Relative to a minimal logical query-language suitable for the game, and a semantic interpretation for that language in terms of context change potentials, we define a logical notion of pertinence, which enables us to arbitrate whether the game is played according to the rules. The elements of pertinence ---contextual consistency, non-entailment, and licensing--- correspond to elements of the Gricean Cooperation Principle. The main novelty is the notion of licensing, by which we can judge whether an utterance is logically related to the context. We illustrate the use of the logic of interrogation in natural language semantics by considering some linguistic examples, which exhibit phenomena which are inherently related to the communicative function of language.