John Keller presents a set of new essays on ontology, time, freedom, God, and philosophical method. Our understanding of these subjects has been greatly advanced, since the 1970s, by the work of Peter van Inwagen. The contributions, from some of the most prominent living philosophers, engage with van Inwagen's work and offer new insights in metaphysics, philosophy of religion, and the philosophy of philosophy. Van Inwagen himself gives selective responses. In metaphysics, the volume will particularly interest philosophers working on free will, relational vs constituent ontologies, and time travel; in philosophy of religion, notable topics include the ontological argument, the compatibility of theism and evolution, the problem of evil, and the doctrine of atonements. And there are three papers on the hot topic of philosophical success, with responses from van Inwagen.