Abstract: This book contains 15 papers by the influential American philosopher, David Lewis. All previously published (between 1966 and 80), these papers are divided into three groups: ontology, the philosophy of mind, and the philosophy of language. Lewis supplements eight of the fifteen papers with postscripts in which he amends claims, answers objections, and introduces later reflections. Topics discussed include possible worlds, counterpart theory, modality, personal identity, radical interpretation, language, propositional attitudes, the mind, and intensional semantics. Among the positions Lewis defends are modal realism, materialism, socially contextualized formal semantics, and functionalism of the mind. The volume begins with an introduction in which Lewis discusses his philosophical method.

Keywords: counterpart theory, epistemology, David Lewis, mereology, metaphysics, modal semantics, ontology, philosophy of language, philosophy of mind