Book excerpt: Paul Tillich's classic work confronts the age-old question of how the moral is related to the religious. In particular, Tillich addresses the conflict between reason-determined ethics and faith-determined ethics and shows that neither is dependent on the other but that each alone is inadequate. Instead, Tillich reveals to us the gift that came with the arrival of Christ: a new reality that offers a power of being in which we can participate and out of which true thought and right action are possible. The Library of Theological Ethics series focuses on what it means to think theologically and ethically. It presents a selection of important and otherwise unavailable texts in easily accessible form. Volumes in this series will enable sustained dialogue with predecessors though reflection on classic works in the field.