Among the most important modern Catholic thinkers, Joseph Ratzinger, later Pope Benedict XVI, fundamentally shaped Christian theology in the 20th and early 21st centuries. His collaborations and debates with figures such as Henri de Lubac, Karl Rahner, Jean Daniélou, Hans Küng, Hans Urs von Balthasar, and Jürgen Habermas reflect the key role he has played in the development of Christian life and doctrine. The Cambridge Companion to Joseph Ratzinger conveys the depth and breadth of his significant legacy to contemporary Catholic theology and culture. With contributions from an international team of scholars, the volume assesses Ratzinger's theological synthesis in response to contemporary challenges that Christianity faces. It surveys the major themes and topics that Ratzinger explored, and highlights aspects of the ideas that he developed in his engagement with a wide variety of intellectual and religious currents. Collectively, the essays in this volume demonstrate how Ratzinger's epochal contributions to Christian thought will reverberate for generations to come.