Napoleon has said that in war the moral element is to all others as three is to one. Moreover, as du Picq impressively demonstrates, while all other circumstances change with time, the human element remains the same, capable of just so much endurance, sacrifice, effort, and no more. Thus, from Caesar to Foch, the essential factor in war endures unmodified. And it is not the value of du Picq's book, as an explanation of the disasters of 1870, but of the triumphs of 1914-18, which gives it present and permanent interest. It is not as the forecast of why Bazaine, a type of all French commanders of the Franco-Prussian War, will fail, but why Foch, Joffre, will succeed, that the volume invites reading to-day. Beyond all else, the arresting circumstances in the fragmentary pages, perfect in themselves but incomplete in the conception of their author, is the intellectual and the moral kinship they reveal between the soldier who fell just before the crowning humiliation of Gravelotte and the victor Champenoise, the Yser and the colossal conflict of 1918 to which historians have already applied the name of the Battle of France, rightly to suggest its magnitude. Read the hastily compiled lectures of Foch, the teacher of de Guerre, recall the fugitive but impressive words of Foch, the soldier, uttered on the spur of the moment, filled with homely phrase, and piquant figure and underlying all, one encounters the same integral conception of war and of the relation of the moral to the physical, which fills the all too scanty pages of du Picq.