This is a 3 volumes set Volume 1 is the introduction with definition, scope, object, sources, methods, history and literature of Moral Theology Volume 2 is sin and the means of grace. Volume 3 is Man's duty to himself. Catholic Moral Theology, broadly speaking, is the scientific exposition of the ethical teaching of the Gospel or more definitely, that theological discipline which sets forth the laws, rules, and precepts man must know and obey in order to attain his supernatural destiny. Moral Theology must avoid two extremes: overemphasizing the ascetic point of view and resolving itself into mere casuistry. In the two preceding volumes of this Handbook we dealt with the general principles of Moral Theology (Theologia Moralis Generalis). We must now show how these general principles are to be applied to man's conduct as an individual and as a member of society (Theologia Moralis Specialis ). The will of God is the supreme and ultimate source of all obligation. Hence, strictly speaking, man has but one duty, namely, to obey the divine law. This law, according to St. Paul, "is charity, from a pure heart, and a good conscience, and an unfeigned faith." 1 St. Gregory the Great says: "The commandments one and all spring solely from love, and together constitute a single precept, because whatever is commanded, is founded upon charity." And St. Thomas Aquinas: "All the commandments are fulfilled in the one law of charity."