Eleven distinguished philosophers have contributed specially written essays on a set of topics much debated in recent years, including physicalism, qualia, semantic competence, conditionals, presuppositions, two-dimensional semantics, and the relation between logic and metaphysics. All these topics are prominent in the work of Robert Stalnaker, a major presence in contemporary philosophy, in honor of whom the volume is published. It also contains a substantial new essay in which Stalnaker replies to his critics, and sets out his current views on the topics discussed.