The book develops the metaphysics of meaning along the lines set up by Paul Grice, defining the three central notions of what is meant, said and implicated. The Gricean notion of what is said is threatened by semantic underdetermination: If the sentence underdetermines the thought it is used to express, what is said cannot be the proposition expressed by the sentence and meant by the speaker. This leads to a number of questions: How far does semantic underdetermination reach? Do we have to extend or restrict the Gricean notion? Is what is said semantic or pragmatic? Keeping these metaphysical questions separate from the epistemological question of how the hearer understands what is meant, which is best explained by generalizing the Gricean theory of implicature derivation and combining it with a game-theoretic model, the book provides an original defense of a Gricean view in the ongoing debate about semantics and pragmatics.