Author's Preface to the English Edition THE work which is herewith in an English version presented to a new circle of readers, appeared originally as a publication of the Görres Gesellschaft, an association of learned men, whose chief object it is to preserve and advance the Christian-Catholic spirit in profane science and education. A number of augmented new editions increased the work to its present size and scope. Intended at first as a defence against certain attacks made upon Catholic Moral Teaching, in popular literature as well as in scientific treatises, my book has thus gradually become an exhaustive statement and vindication of the principles of Catholic morality -- principles which in our day receive much discussion in Protestant and liberal-philosophical circles, and which are often represented as being inconsistent with the demands of modern culture. In dealing with these principles I followed a method, which, while firmly rooted in ecclesiastical teaching and tradition, nevertheless strives to keep in view the demands of modern religious and scientific life, and it has not only found much approval among educated Catholics, clergy as well as laity, but has also made in many instances a deep and favourable impression upon unprejudiced Protestants. It is obvious that the demands made upon apologetics, and upon the treatment of its subject, differ according to the various needs of different countries and peoples. However, it is just as obvious that the principles and most important points of controversy, especially in matters of morality, are to-day universal and they recognize no intellectual boundaries. In English and in German speaking countries the influence of Protestant thought and sentiment is much the same. The accusations, partly malicious, against the practise of confession, against casuistry in morals, etc., find a ready reception with nearly all opponents of the Church. Serious lack of understanding and radical misconception, regarding the conscience and its relation to God and to Church authority, sin and salvation, the moral law and its relation to liberty, justification, interior and exterior action of grace, ecclesiastical and worldly life, permeate contemporaneous non-Catholic theology and literature. To these must be added the important questions of public morality, of obedience to State and Church, of economic independence and unity, of Catholic organization and permissible union of action with other creeds, all questions upon which even within the Church there exist differences of opinion that have led to important expressions by ecclesiastical authority. The discussion of such matters must arouse in every thinking man a lively interest, and there are many points in science and economics that interest equally the people of America, England, and Germany. Some statements, especially in the introduction, indicate that the matters that gave rise to them had their origin in Germany, so that an adaptation to conditions closer to readers of this English version might have seemed in place. The translator, however, has refrained from any such attempt, and I believe correctly so, because such matters do not interfere here with the objective statement of questions and points, they rather aid by giving it a concrete form. Furthermore, I remember that in reading German translations of English works, those of Newman, Manning, and Gibbons for instance, the tracing of thought and principles to their origin and individuality seemed to me to be rather an attraction than an obstacle to their full appreciation. May my book in this English edition spread and deepen the conviction of the truth, grandeur, and beauty of Catholic moral teaching, and thus contribute to the honour and better understanding of the Church, and to the consolation and encouragement of the faithful. THE AUTHOR. MÜNSTER, August, 1914.