The author's previously published works both in German and in English have established him as a Christian philosopher whose message should be heeded. As a specialist in the field of Christian Ethics, Professor Von Hildebrand is here concerned with exploring the nature of true Christian morality. In so doing he devotes a large part of his book to counterfeits of morality which he detects both in the mores of the present generation and in much of our current literature. Two of these counterfeit moralities, the errors of which he would expose, he designates as ""circumstance ethics"" and ""sin mysticism"". He observes in modern life a practical denial of any absolute standard of right and wrong, the thesis being that the rightness or wrongness of a particular line of action is determined by the circumstances prevailing at the time. ""Sin mysticism"" projects into sin "" a mysterious depth, a halo of tumility"". It is this trend that makes the sinner the hero in so many modern novels and dramas. This is a book which will appeal to Catholics of a philosophical mind, although the implications of what Dr. Von Hildebrand has to say affect the life of every modern man.