one to which this study aims to make some contribution, however small. The first part of the book is a study of the motives of war. It is an analysis of the motives of war in the light of the general principles of the development of society. We wish to see what the causes of past wars have been, but we wish also to know what these motives are as they may exist as forces in the present state of society. In such a study, practical questions can never be far away. We can no longer study war as an abstract psychological problem, since war has brought us to a horrifying and humiliating situation. We have discovered that our modern world, with all its boasted morality and civilization, is actuated, at least in its relations among nations, by very unsocial motives. We live in a world in which nations thus far have been for the most part dominated by a theory of States as absolutely sovereign and independent of one another. Now it becomes evident that a logical consequence of that theory of States is absolute war. A prospect of a future of absolute war in a world in which industrial advances have placed in the hands of men such terrible forces of destruction, an absolute warfare that can now be carried into the air and under the sea is what makes any investigation of the motives of war now a very practical problem. If the urgency of our situation drives us to such studies and makes us hasten to apply even an immature sociology and psychology, it ought not to prejudice our minds and make us, for example, fall into the error of wanting peace at any price--an ideal which, as a practical national philosophy, might be even worse than a spirit of militarism. What we need to know, finally, in order to avoid these errors which at least we may imagine, is what, in the most fundamental way, progress may be conceived to be. If we could discover that, and set our minds to the task of making the social life progressive, we might be willing to let wars take care of themselves, so to speak, without any radical philosophy of good and evil. We ought at least to examine war fairly, and to see what, in the waging of war, man has really desired. A study of war ought to help us to decide whether we must accept our future, with its possibility of wars, as a kind of fate, or whether we must now begin, with a new idea of conscious evolution, to apply our science and our philosophy and our practical wisdom seriously for the first time to the work of creating history, and no longer be content merely to live it.