So far there has been a dearth of works on Moral Theology in English; and it is this want that has occasioned the present work, which aims at presenting Moral Theology, not only in its essentials, but even more in detail and with greater fullness than is done by most of the text-books commonly in use. And yet, while pursuing this larger and more comprehensive plan, the authors of this new work have tried to be as brief and compact as possible. It has been their endeavor especially to avoid digressions into other fields and to sum up pertinent matter in as clear and simple a manner as the subjects treated will permit. 17. The Division and Order of Parts in Moral Theology.--The arrangement of his matter made by St. Thomas Aquinas in the _Summa Theologica_ is admittedly unsurpassed and unsurpassable in the qualities that good distribution should have, viz., clearness, connection between parts, completeness. Hence, we cannot do better than follow the order he has used in his treatment of moral subjects. His general division is as follows: (1) The Last End of Man.--From the Last End acts derive their morality, those being good that advance man towards its attainment, and those evil that turn him away from its possession. The Last End is considered; (a) as to its existence; (b) as to its nature (i.e., the constituents of supreme beatitude). (2) The General Means Tending to the Last End.--God is approached, not by the steps of the body, but by the operations of the soul, and thus it is human acts that lead one to one’s Last End. These acts are considered: (a) as they are in themselves or absolutely, and according to the twofold division of acts proper to man (human acts) and acts common to man and beast (passions); (b) as to the internal principles from which they proceed, i.e., habits, whether good (virtues) or bad (vices); (c) as to the external principles by which they are influenced. The external principle of evil is the demon, who tempts man to sin. The external principle of good is God, who instructs us by His law and the voice of conscience, and assists us by His grace. (3) The Special Means Tending to the Last End.--These are our own good works; hence, here are considered the virtues incumbent on all classes of men, i.e., the theological and moral virtues. 18. Some of the topics just mentioned (e.g., divine grace) are discussed fully in works on Dogmatic Theology, and hence may be omitted here. Again, since the Last End of man is considered at great length in dogmatic works on Eschatology, little need be said about it here. Hence, it will be convenient to divide this work into two parts as follows: General Moral Theology, in which are treated the more remote principles on duty, such as the Last End, human acts, good and bad habits, laws and conscience, grace; (b) Special Moral Theology, in which are treated the more immediate rules concerning duty, i.e., man’s obligations as regards the virtues and the Commandments. PART I