Vatican II represents a watershed in the history of Catholic ecclesiology. Although it stands in organic continuity with previous magisterial teaching, distortions of its teaching have proliferated since the time of the Council, leading many to conclude that the Catholic Church changed her position regarding the identity that exists between the One Church of Christ and the Catholic Church.

Stephen A. Hipp's The One Church of Christ: Understanding Vatican II refutes that conclusion and explains the Catholic understanding of how Christ's indivisible Church relates to the Catholic Church, to non-Catholic Christian communities, and to other religious societies. Hipp thoroughly examines the controversial statement that "the Church of Christ subsists in the Catholic Church" from terminological, historical, and theological perspectives, showing that Vatican II introduces nothing doctrinally new to the Church's self-understanding, but provides a more nuanced way of speaking about the unicity and universality that define Christ's Church. He reveals that Vatican II thereby establishes ecumenism and interreligious dialogue on fruitful ground, while calling Catholics to a greater appreciation of the extraordinary gift of the Church's subsistence.