The Roman Catholic Church has been remarkably active in ecumenical discussions in the last number of years, but that has not always been the case. ! describes the dramatic process that led to the Vatican Secretariat for Promoting Christian Unity, and the definitive commitment of the Roman Catholic Church to the universal ecumenical movement. It gives insightful profiles of the principal actors in this ecumenical drama -- Pope John XXIII, Cardinal Lorenz Jaeger of Paderborn, Germany, and Cardinal Augustin Bea, S.J. -- in the political, social, and theological ambivalence of a postwar divided Germany. It also provides insight into the negotiations that paved the way for the unprecedented ecumenical openness of Vatican II. An engaging story, opens a window into the events that have shaped the modern Catholic Church and highlights the context shaping the theological development of Pope Benedict XVI.