The Art of War has been very simply defined as 'the art which enables any commander to worst the forces opposed to him.' It is therefore conversant with an enormous variety of subjects: Strategy and Tactics are but two of the more important of its branches. Besides dealing with discipline, organization, and armament, it is bound to investigate every means which can be adapted to increase the physical or moral efficiency of an army. The author who opened his work with a dissertation on 'the age which is preferable in a generalissimo, ' or 'the average height which the infantry soldier should attain, ' was dealing with the Art of War, no less than he who confined himself to purely tactical speculations. The complicated nature of the subject being taken into consideration, it is evident that a complete sketch, of the social and political history of any period would be necessary to account fully for the state of the 'Art of War' at the time. That art has existed, in a rudimentary form, ever since the day on which two bodies of men first met in anger to settle a dispute by the arbitrament of force. At some epochs, however, military and social history have been far more closely bound up than at others. In the present century wars are but episodes in a people's existence: there have, however, been times when the whole national organization was founded on the supposition of a normal state of strife. In such cases the history of the race and of its 'art of war' are one and the same