In the next place we have omitted all descriptions of battles. Our reasons for this are simple. The strategy of a campaign or of a single battle is a highly technical, and usually a highly controversial, matter about which experts differ widely. In the field of military and naval operations most writers and teachers of history are mere novices. To dispose of Gettysburg or the Wilderness in ten lines or ten pages is equally absurd to the serious student of military affairs. Any one who compares the ordinary textbook account of a single Civil War campaign with the account given by Ropes, for instance, will ask for no further comment. No youth called upon to serve our country in arms would think of turning to a high school manual for information about the art of warfare. The dramatic scene or episode, so useful in arousing the interest of the immature pupil, seems out of place in a book that deliberately appeals to boys and girls on the very threshold of life's serious responsibilities. It is not upon negative features, however, that we rest our case. It is rather upon constructive features. _First._ We have written a topical, not a narrative, history. We have tried to set forth the important aspects, problems, and movements of each period, bringing in the narrative rather by way of illustration. _Second._ We have emphasized those historical topics which help to explain how our nation has come to be what it is to-day. _Third._ We have dwelt fully upon the social and economic aspects of our history, especially in relation to the politics of each period. _Fourth._ We have treated the causes and results of wars, the problems of financing and sustaining armed forces, rather than military strategy. These are the subjects which belong to a history for civilians. These are matters which civilians can understand--matters which they must understand, if they are to play well their part in war and peace. _Fifth._ By omitting the period of exploration, we have been able to enlarge the treatment of our own time. We have given special attention to the history of those current questions which must form the subject matter of sound instruction in citizenship. _Sixth._ We have borne in mind that America, with all her unique characteristics, is a part of a general civilization. Accordingly we have given diplomacy, foreign affairs, world relations, and the reciprocal influences of nations their appropriate place.