Ways a World Might Be collects, and adds to, Robert Stalnaker's published papers on metaphysical issues. The central theme that runs throughout the book is the role of possible worlds in articulating our various metaphysical commitments. The essays contain both reflections on the general idea of a space of possbilities and attempts to use the framework of possible worlds to formulate and clarify semantic and metaphysical questions about properties and individuals, supervenience and essentialism, reference, thought, and experience. The essays also reflect on the nature of metaphysics, and on the relation between metaphysical and semantic questions - questions about what there is and questions about how we talk and think about what there is.