Descartes' Meditations is one of the most thoroughly analyzed of all philosophical texts. Nevertheless, central issues in Descartes' thought remain unresolved, particularly the problem of the Cartesian Circle. Most attempts to deal with that problem have weakened the force of Descartes' own doubts or weakened the goals he was seeking. In this book, Stephen I. Wagner gives Descartes' doubts their strongest force and shows how he overcomes those doubts, establishing with metaphysical certainty the existence of a non-deceiving God and the truth of his clear and distinct perceptions. Wagner's innovative and thorough reading of the text clarifies a wide range of other issues that have been left unclear by previous commentaries, including the nature of the cogito discovery and the relationship between Descartes' proofs of God's existence. His book will be of great interest to scholars and upper-level students of Descartes, early modern philosophy and theology.