That there was need of a book on the subject of which this treats, will be evidenced to those who examine its contents. Whether this book meets the need, it is for those to decide who are its readers. The circumstances of its writing are recited in its opening chapter. I was urged to the undertaking by valued friends. At every step in its progress I have been helped by those friends, and others. For much of that which is valuable in it, they deserve credit. For its imperfections and lack, I alone am at fault. Although I make no claim to exhaustiveness of treatment in this work, I do claim to have attempted a treatment that is exceptionally comprehensive and thorough. My researches have included extensive and varied fields of fact and of thought, even though very much in those fields has been left ungathered. What is here presented is at least suggestive of the abundance and richness of the matter available in this line. While not presuming to think that I have said the last word on this question of the ages, I do venture to hope that I have furnished fresh material for its more intelligent consideration. It may be that, in view of the data here presented, some will settle the question finally for themselves-by settling it right. If the work tends to bring any considerable number to this practical issue, I shall be more than repaid for the labor expended on it; for I have a profound conviction that it is the question of questions in ethics, now as always.