In God as Reason: Essays in Philosophical Theology, Vittorio Hösle presents a systematic exploration of the relation between theology and philosophy. In examining the problems and historical precursors of rational theology, he calls on philosophy, theology, history of science, and the history of ideas to find an interpretation of Christianity that is compatible with a genuine commitment to reason. The essays in the first part of God as Reason deal with issues of philosophical theology. Hösle sketches the challenges that a rationalist theology must face and discusses some of the central ones, such as the possibility of a teleological interpretation of nature after Darwin, the theodicy issue, freedom versus determinism, the mindbody problem, and the relation in general between religion, theology, and philosophy. In the essays of the second part, Hösle studies the historical development of philosophical approaches to the Bible, the continuity between the New Testament concept of pneuma and the concept of Geist (spirit) in German idealism, and the rationalist theologies of Anselm, Abelard, Llull, and Nicholas of Cusa, whose innovative philosophy of mathematics is the topic of one of the chapters. The book concludes with a thorough evaluation of Charles Taylor's theory of secularization. This ambitious work will interest students and scholars of philosophical theology and philosophy of religion as well as historians of ideas and science.