Part I of this book is a concise exposition of the expression theory of meaning, according to which meaning consists in the expression of thoughts, their component ideas, or other mental states. The theory is founded on the fact that thoughts are event types with a constituent structure, and that thinking is a fundamental propositional attitude distinct from belief. It can account for interjections, syncategorematic terms, pejorative terms, conventional implicatures, and other cases of nondescriptive meaning that have long been seen as difficult for both ideational and referential theories of meaning. Part II defends the analysis of speaker and word reference in terms of the expression of ideas by exploring the vague connection of reference with predication, and reviewing the difficulties of alternative approaches, both descriptivist and causal. Part III shows how the expression theory can account for the meaning of names, and the distinctive way in which their meaning determines their reference. The problems with Millian theories show that the meaning of a name consists in the expression of an idea. The problems with Fregean theories show that the ideas expressed by names are atomic or basic. A name is directly and rigidly referential because the extension of the idea it expresses is not determined by the extensions of component ideas. This account of names does not preclude the use of a possible worlds or situation semantics to systematize their formal referential properties. The referential properties of ideas can also be set out recursively by providing a generative theory of ideas, assigning extensions to atomic ideas, and formulating rules whereby the semantic value of a complex idea is determined by the semantic values of its contents. Arguments for the logical necessity of identity statements expressed using non-synonymous names are shown to be unsound, along with various twin earth arguments.