In short, the Staff must ask of them what is the policy which your diplomacy is pursuing, and where, and why, do you expect it to break down and force you to take up arms?  The Staff has to carry on in fact when diplomacy has failed to achieve the object in view, and the method they will use will depend on the nature of that object.  So we arrive crudely at our theory that war is a continuation of policy, a form of political intercourse in which we fight battles instead of writing notes.

It was this theory, simple and even meaningless as it appears at first sight, that gave the key to the practical work of framing a modern war plan and revolutionised the study of strategy.  It was not till the beginning of the nineteenth century that such a theory was arrived at.  For centuries men had written on the “Art of War,” but for want of a working theory their labours as a whole had been unscientific, concerned for the most part with the discussion of passing fashions and the elaboration of platitudes.  Much good work it is true was done on details, but no broad outlook had been obtained to enable us to determine their relation to the fundamental constants of the subject.  No standpoint had been found from which we could readily detach such constants from what was merely accidental.  The result was a tendency to argue too exclusively from the latest examples and to become entangled in erroneous thought by trying to apply the methods which had attained the last success to war as a whole.  There was no means of determining how far the particular success was due to special conditions and how far it was due to factors common to all wars.

It was the Revolutionary and Napoleonic wars, coinciding as they did with a period of philosophic activity, that revealed the shallowness and empirical nature of all that had been done up to that time.  Napoleon’s methods appeared to his contemporaries to have produced so strenuous a revolution in the conduct of land warfare that it assumed a wholly new aspect, and it was obvious that those conceptions which had sufficed previously had become inadequate as a basis of sound study.  War on land seemed to have changed from a calculated affair of thrust and parry between standing armies to a headlong rush of one nation in arms upon another, each thirsting for the other’s life, and resolved to have it or perish in the attempt.  Men felt themselves faced with a manifestation of human energy which had had no counterpart, at least in civilised times.

The assumption was not entirely true.  For although the Continent had never before adopted the methods in question, our own country was no stranger to them either on sea or land.  As we shall see, our own Revolution in the seventeenth century had produced strenuous methods of making war which were closely related to those which Napoleon took over from the French Revolutionary leaders.  A more philosophic outlook might have suggested that the phenomenon was