Catholic theology has to face a certain number of fundamental questions: what is the nature and content of Christian revelation, what are the sources of revelation, how are the mysteries of the faith to be understood in relation of one to another, and how do the truths of the Catholic faith relate to the acquisitions of natural reason. In the contemporary context, Catholic theology is marked by a diversity of approaches, many of which are seemingly incompatible or estranged from one another. How might we think about the unity of Catholic theology over and above the diversity of forms? What role, if any, can Aquinas play as a common doctor in facilitating exchanges between theological traditions in the Church? Principles of Catholic Theology seeks to address directly the nature of Catholic theology and the challenge of its contemporary articulation with an eye towards its articulation in its Thomistic key. This book is also the first of a series of collections of essays by Thomas Joseph White, OP, extending over a range of fundamental topics in Catholic dogmatic theology.