Despite the length of this book, critics will undoubtedly note omissions. Confronting the writer of every textbook of history is the eternal problem of selection--the choice of what is most pointedly significant from the sum total of man's thoughts, words, and deeds. It is a matter of personal judgment, and personal judgments are notoriously variant. Certainly there will be critics who will complain of the present author's failure to follow up his suggestions concerning sixteenth-century art and culture with a fuller account of the development of philosophy and literature from the seventeenth to the twentieth century; and the only rejoinders that the harassed author can make are the rather lame ones that a book, to be a book, must conform to the mechanical laws of space and dimension, and that a serious attempt on the part of the present writer to make a synthesis of social and political facts precludes no effort on the part of other and abler writers to synthesize all these facts with the phenomena which are conventionally assigned to the realm of "cultural" or "intellectual" history. In this, and in all other respects, the author trusts that his particular solution of the vexatious problem of selection will prove as generally acceptable as any. In the all-important matter of accuracy, the author cannot hope to have escaped all the pitfalls that in a peculiarly broad and crowded field everywhere trip the feet of even the most wary and persistent searchers after truth. He has naturally been forced to rely for the truth of his statements chiefly upon numerous secondary works, of which some acknowledgment is made in the following _Note_, and upon the kindly criticisms of a number of his colleagues; in some instances, notably in parts of the chapters on the Protestant Revolt, the French Revolution, and developments since 1848 in Great Britain, France, and Germany, he has been able to draw on his own special studies of primary source material, and in certain of these instances he has ventured to dissent from opinions that have been copied unquestioningly from one work to another. No period of history can be more interesting or illuminating than the period with which this book is concerned, especially now, when a war of tremendous magnitude and meaning is attracting the attention of the whole civilized world and arousing a desire in the minds of all intelligent persons to know something of the past that has produced it. The great basic causes of the present war the author has sought, not in the ambitions of a single power nor in an isolated outrage, but in the history of four hundred years. He has tried to write a book that would be suggestive and informing, not only to the ordinary college student, but to the more mature and thoughtful student of public affairs in the university of the world. CARLTON J. H. HAYES. AFTON, NEW YORK, May, 1916. NOTE OF ACKNOWLEDGMENT