As a student of land forms who is more or less familiar with the broader topographic features of Europe the writer has had a professional as well as a personal interest in the great war. He was particularly anxious to discover how far modern military operations are still affected by the element of terrain; and whether guns which hurl high explosive shells with marvelous accuracy over lofty mountain ridges and across the widest river valleys, aeroplane service which permits better observations than can be secured from the most favorably situated topographic eminences, and modem engineering devices which refuse to be daunted by the deepest stream or steepest cliff, have eliminated the surface features of the land as an important factor in military calculations. Aided by large scale maps showing with precision the topography of the principal battle fronts he has, from the first days of tho war, followed with some care the changes on each front, and has found ample indication that the role played by land forms in plans of campaign and movements of armies is no less important today than in the past. To emphasize this interesting relationship between inanimate Nature and the science of war is one of the objects of this book.<br><br>Another object, and perhaps the more important, is to place before the reader such a picture of each theater of war as shall enable him to follow with greater ease and livelier interest the movements of our own and our Allies' troops.