The Second Vatican Council of the Catholic Church (1962-65) was a truly revolutionary event, not only for the 1.3 billion Catholics, nor even just for all Christians, but for all religious and non-religious persons of the world. Before then the leaders of the Catholic Church adamantly opposed Catholics’ engaging in dialogue with non-Catholics. Vatican II, however, insisted that “Catholics must...take the first steps” in dialogue toward the Other, whether Christian, of another religion, or non-religious! Vatican II also committed “all Catholics, wherever necessary, to undertake with vigor the task of renewal and reform,” embracing—as Pope St. John XXIII expressed it—aggiornamento (“bringing up to date”) so the Church may open itself to dialogue. It declared that “Church renewal therefore has notable ecumenical [dialogue] importance.” It is to Vatican II’s reform and encouragement of dialogue that the Ecumenical Press Vatican II Series is dedicated.