I began work on thought, belief, and desire shortly after I graduated from the University of Michigan in 1973, inspired by Alvin Goldman and his A Theory of Human Action, along with Stephen Stich, Arthur Burks, John Perry, and Jaegwon Kim. That work grew into my doctoral dissertation (Princeton University, 1977), directed by David Lewis, Gilbert Harman, and Richard Jeffrey. I remain indebted to these outstanding philosophers not only for key ideas but also for instilling a love of philosophy. The dissertation became a book-length manuscript entitled “Elements of Psychology: Belief, Desire, and Thought.” When a chapter on meaning took on the proportions of a book all by itself, I decided to first complete the present volume, Meaning, Expression, and Thought. Many of the ideas on thought presented in Part III were first developed in my dissertation and elaborated in “Belief, Desire, and Thought.” I use them here to provide the psychological foundations for the theory of meaning developed in the rest of this work. This book was delayed by my recent Implicature (1998), which explains why Grice's great “synthetic” project gets so much less attention here than his “analytic” project. I wrote Meaning, Expression, and Thought, furthermore, in tandem with my forthcoming Nondescriptive Meaning and Reference, which applies the expression theory of meaning to names, indexicals, and other special cases, develops the expression theory of reference in greater depth, and shows how referential semantics can be treated in the expression theory.