This book critically assesses arguments for the existence of the God of classical theism, develops an innovative account of objects' persistence, and defends new arguments against classical theism. The authors engage the following classical theistic proofs: Aquinas's First Way, Aquinas's De Ente argument, and Feser's Aristotelian, Neo-Platonic, Augustinian, Thomistic, and Rationalist proofs.  The authors also provide the first systematic treatment of the 'existential inertia thesis'.  By connecting the thesis to relativity theory and recent developments in the philosophy of physics, and by developing a variety of novel existential-inertia-friendly explanations of persistence, they mount a formidable new case against classical theistic proofs. Finally, they defend new arguments against classical theism based on abstract objects and changing divine knowledge. The text appeals to students, researchers, and others interested in classical theistic proofs, the existence and nature of God, and the ultimate explanations of persistence, change, and contingency.