Contemporary Roman Catholics have realized in the last thirty-five years that when an ecumenical council has concluded, it is far from over. The interpretation of the decrees of the Second Vatican Council has become today as critical and controverted as the formulation of the decrees was during the Council itself. The present controversies centre on ecclesiology—the nature of the Church—and questions at issue concern continuity and innovation. Did Vatican II, and especially the Decree on the Church in the Modern World, reform the structure and the governance of the Church toward a greater degree of consultation, subsidiarity, decentralization—‘collegiality’, to use the expression of the Council itself? Or was the vision of the Council for the Church in basic continuity with the centralized, papal-monarchial Church of the First Vatican Council? Around these questions centres most of the contention that engages the Church today: debates having to do with the rôle of bishops’ conferences, the operation of the Roman curia, the relationship of the magisterium or teaching authority to theologians.