This work is an extensive military history of World War One, the Great War. The book begins with the reasoning behind the "inevitable" war, deeply covers the military actions, technology, and strategery, and concludes with the peace proceedings. Some political history is also included.

From the original foreword when the book was published in 1918: "This is a popular narrative history of the world's greatest war. Written frankly from the viewpoint of the United States and the Allies, it visualizes the bloodiest and most destructive conflict of all the ages from its remote causes to its glorious conclusion and beneficent results. The world-shaking rise of new democracies is set forth, and the enormous national and individual sacrifices producing that resurrection of human equality detailed."Two ideals have been before us in the preparation of this necessary work. These are simplicity and thoroughness. It is of no avail to describe the greatest of human events if the description is so confused that the reader loses interest. Thoroughness is an historical essential beyond price. So it is that official documents prepared in many instances upon the field of battle, and others taken from the files of the governments at war, are the basis of this work. Maps and photographs of unusual clearness and high authenticity illuminate the text. All that has gone into war making, into the regeneration of the world, are herein set forth with historical particularity. The stark horrors of Belgium, the blighting terrors of chemical warfare, the governmental restrictions placed upon hundreds of millions of civilians, the war sacrifices falling on all the civilized peoples of earth, are in these pages."It is a book that mankind can well read and treasure."With an introduction by General Peyton C. March, Chief of Staff of the United States Army.