Acting on Principles, the product of over thirty years of teaching, gives a comprehensive overview of the Moral Theology of St. Thomas Aquinas, placing it in dialogue with contemporary ethical theory and developments in Catholic theology since the Second Vatican Council. Suitable for students of ethics and moral theology, and general readers seeking Christian guidance in the formation of conscience and moral decision making, it presents the classical Catholic ethical tradition in a clear and lively style. ""Fr. Zagar offers us a study that is at once scholarly and accessible to a wide readership. Faithful to the thought and method of St. Thomas, Acting on Principles is a splendid resource for teachers, students of moral theology, pastors, catechists, and for all who seek to understand more fully the basis for moral judgment. I am delighted to recommend to you this important work "" --Michael Sweeney, O.P. President Dominican School of Philosophy and Theology ""Acting on Principles is, in its essence, a profound appreciation of the moral theology of St. Thomas Aquinas, its relevance to contemporary ethics in the light of the Second Vatican Council, and the culmination of over thirty years of study, teaching, and prayer. Father Zagar's lifetime of teaching renders his writing lucid and accessible. This book will long serve as an invaluable resource for seminarians, catechetical programs, and independent study."" --Fr. Emmerich Vogt, O.P. Prior Provincial Western Dominican Province ""As the fiftieth anniversary of the Second Vatican Council approaches, today's hope is to find ways to blend, in creative fidelity, the moments of continuity and discontinuity that were endorsed by the Council. Janko Zagar's Acting on Principles, which began to take shape in the first decades following the Council, exemplifies the ongoing quest for a synthesis true both to the Thomistic legacy and to a Conciliar sense of personalism."" --Richard Schenk O.P. Regent of Studies, Graduate Theological Union, Berkeley Western Dominican Province Fr. Janko Zagar, O.P., a Catholic priest of the Dominican Order, is Emeritus Professor of Moral Theology and former Academic Dean of the Dominican School of Philosophy and Theology at the Graduate Theological Union in Berkeley, California. He is author of Bentham et la France, as well as numerous articles on moral theology and the thought of St. Thomas Aquinas.