This book is a selection of published papers in philosophy of language by Michael Devitt, accompanied by many new footnotes and postscripts. A dominant theme is the semantics of proper names, definite descriptions, and demonstratives. The book argues that these terms have conventional “referential” uses to express “singular” thoughts. Those uses are explained by a unified “causal” theory: a term’s reference is largely fixed in an object by a causal link between the person and the object when it is, or was, the focus of that person’s perception. Furthermore, the book argues that a term’s meaning is its largely causal mode of reference. So, a related theme is the rejection of the “direct reference” view that the meaning of a name is its bearer. A governing idea is naturalism. Languages are parts of the spatio-temporal world playing causal roles in virtue of certain properties, “meanings”. The task of a theory of language is then to explain the nature of those causally significant properties. Naturalism leads to a rejection of the received view that theories of language must rest on an evidential base of speakers’ intuitions and to a search for a respectable empirical base. Another major theme concerns thoughts and their ascriptions. The book has chapters on Putnam’s problem of determining reference; on the application of Kripke’s idea of “rigidity” to general terms; on the vexed question of distinguishing linguistic phenomena that are “semantic” from those that are “pragmatic”.