Josian Royce's late masterpiece, The Problem of Christianity, is based on a series of lectures he delivered at Manchester College, Oxford, in 1913. It presents his philosophical interpretation of Christianity's fundamental ideas--community, sin, atonement, and saving grace; shows their relevance to the current confluence of world religions; and grounds his position upon a personal transformation into genuine loyalty toward the community of the entire human family. The Problem opens up a mine of surprising treasures while its prophetic voice speaks to contemporary issues and current movements in ecumenics and inter-religious dialogue. Frank M. Oppenheim's new introduction highlights its relevance to some of the pressing problems of the new century. "A notable contribution to the interpretation of Christian ideas."--The Nation "Royce has contributed largely to the treasures of religious thought."--New York Times