The Second Vatican Council (1962–1965) radically shook up many centuries of tradition in the Roman Catholic Church. This book by Thomas Guarino, a noted expert on the sources and methods of Catholic doctrine, investigates whether Vatican II’s highly contested teachings on religious freedom, ecumenism, and the Virgin Mary represented a harmonious development of—or a rupture with—Catholic tradition. Guarino’s careful explanations of such significant terms as continuity, discontinuity, analogy, reversal, reform, and development greatly enhance and clarify his discussion. No other book on Vatican II so clearly elucidates the essential theological principles for determining whether—and to what extent—a conciliar teaching is in continuity or discontinuity with antecedent tradition. Readers from all faith traditions who care about the logic of continuity and change in Christian teaching will benefit from this masterful case study.