This high proportion of history's decisive campaigns, the significance of which is enhanced by the comparative rarity of the direct approach, enforces the conclusion that the indirect is by far the most hopeful and economic form of strategy.

The practical value of history is to throw the film of the past through the material projector of the present on to the screen of the future.

I used to think that the causes of war were predominantly economic. I came to think that they were more psychological. I am now coming to think that they are decisively "personal," arising from the defects and ambitions of those who have the power to influence the currents of nations.

Direct experience is inherently too limited to form an adequate foundation either for theory or for application. At the best it produces an atmosphere that is of value in drying and hardening the structure of thought. The greater value of indirect experience lies in its greater variety and extent. History is universal experience, the experience not of another, but of many others under manifold conditions.

If you find your opponent in a strong position costly to force, you should leave him a line of retreat as the quickest way of loosening his resistance. It should, equally, be a principle of policy, especially in war, to provide your opponent with a ladder by which he can climb down.

With growing experience, all skillful commanders sought to profit by the power of the defensive, even when on the offensive.

Air Power is, above all, a psychological weapon - and only short-sighted soldiers, too battle-minded, underrate the importance of psychological factors in war.