The military historian who writes of past centuries has in some ways an easier task than one who attempts to put contemporary events into their historical perspective. In the first place, with every desire to be accurate, the latter finds that the accounts of eye-witnesses differ so much that he is forced to form his own conclusions, and to adopt what, according to his judgment, is the most probable version. In the second place, after reading a private letter giving a graphic account of a particular part of a battle, he may easily derive a totally false impression of the whole. Moreover, he writes in the constant presence of the criticism of eye-witnesses. A special difficulty also arises from the unequal quality of the material placed at his disposal. There is sometimes a wealth of information on unimportant incidents and no material for the history of important or dramatic events, in which the principal actors were almost invariably killed. Even the Battalion diaries, which were kept with meticulous accuracy during the early days of the war, contain less and less material as the fighting became more and more serious. With a war of such astounding magnitude, when millions of men are fighting on a front of hundreds of miles, any attempt to give an intelligible picture of what is going on in a modern battle becomes practically impossible. Even if such a course were desirable in a regimental history, the material supplied, which consists for the most part of letters and diaries of regimental officers, would be totally inadequate, since regimental officers know little of what is going on except in their immediate neighbourhood. A tactical study was out of the question, since a battalion plays such a small part in modern battles, and to describe the movements of corps and armies appeared to be beyond the scope of a regimental history. I therefore decided to depart from tradition, and to write a narrative giving, as far as I was able, details about companies, and even platoons. It seemed to me that this was what the officers themselves would prefer. The absence of information concerning the German Army necessarily takes some of the life and colour out of such a record as this. In all military histories the account of the enemy's movements adds enormously to the interest of the narrative; but at present, beyond a few accounts from neutral journalists inspired by the Germans, there is no authentic information as to the movements of the German Army, and the motives which actuated the German General Staff can only be inferred.