The strongest grounds for accepting Arthur Marder’s judgement on how effectively the Services have utilised the past in developing war theory must be that they were too busy assiduously applying the past as a key to unlock the future to bother too much about the present. This was certainly the case until after the Second World War, when mathematicians and social scientists shouldered aside historians as the most valued consorts of the military. Prior to that war, past experience-that is to say, history-had been used extensively: both practically applied in the training of officers, and used theoretically in developing the ‘principles of war’ and in devising tactical doctrine and strategic hypotheses with which to engage the next enemy. History has, until not long since, been much used in developing war theory in its most general sense, nowhere more so than in Great Britain. It seems possible to argue that it has been much mis-used; or, more accurately, its use has been misunderstood and its findings misapplied. Analysis of how this has occurred helps explain why it is that, in the words of one historian, ‘we have steadily lost confidence in the continuing relevance of the recent past’.2 It also demonstrates that history may still have its uses; and that an awareness of its past mis-use may in fact make it a better help-meet to the war theorist than ever it was.