Examines Joseph Ratzinger/Pope Benedict XVI's manifold contributions to Catholic-Protestant theological reflection. The collection opens with an introduction comparing Ratzinger's approach to ecumenism to that of Karl Rahner. Rahner argues that the structural uniting of Protestants and Catholics should take place now without worrying about doctrinal differences. In contrast, Ratzinger argues that unity in Christ requires probing the doctrinal differences and seeking a deeper understanding of the reasoning of each side - on the grounds that the truth of the Gospel that each side desires to preserve will ultimately be the basis for the only kind of Christian ecclesial unity worth having, namely, a unity of the basis of the truth of the Gospel of Jesus Christ.

Detailed essays follow, treating a number of loci including papal primacy, ecumenical principles, liturgy, evangelization, Mariology, Christ's birth and the celebration of Christmas, public theology, Christocentrism, Martin Luther, charity, conscience, missiology, justification, the reception of Ratzinger/Benedict in Radical Orthodoxy, and Scripture and Tradition. These essays run the full gamut of Ratzinger/Benedict's major themes and preoccupations.

Ten of the essays are by Catholic scholars, and seven by Protestant scholars. Contributors include many of the world's leading Ratzinger experts, and the volume opens with an essay by Bishop Rudolf Voderholzer, Director of the Pope Benedict XVI Institute in Regensburg, Germany.