Book excerpt: The Second Vatican Council’s declaration Dignitatis Humanae marks a significant advance over prior magisterial teaching about the right to religious liberty, yet the nature of this advance has long been subject to controversy. Is it a true development, conserving and extending what came before? Or does it instead chart a new course entirely, rejecting and replacing the older teaching? In Religious Liberty and the Hermeneutic of Continuity, R. Michael Dunnigan takes up these pressing questions and offers a careful examination of how the claims of Dignitatis Humanae relate to the magisterial precedents set by the papacy in the nineteenth century. With precision and nuance, Dunnigan analyzes the object, scope, and foundation of the right to religious liberty itself, and his analysis culminates in the proposal that the “right” endorsed by Vatican II is not identical with the “rights” condemned by previous popes. Beyond establishing the claims of Dignitatis Humanae as a true development of prior teaching, Dunnigan shows that its contribution to the question of religious liberty has not yet received full appreciation. Indeed, Dunnigan demonstrates how the Vatican II declaration reaffirms, reinforces, and even revivifies prior magisterial teaching on religious liberty through its emphasis on human integrity, which emerges as a foundational but often overlooked principle of continuity.