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.

It should be the aim of grand strategy to discover and pierce the Achilles' heel of the opposing government's power to make war. Strategy, in turn, should seek to penetrate a joint in the harness of the opposing forces. To apply one's strength where the opponent is strong weakens oneself disproportionately to the effect attained. To strike with strong effect, one must strike at weakness.

While hitting one must guard ... In order to hit with effect, the enemy must be taken off his guard.

Air forces offered the possibility of striking a the enemy's economic and moral centres without having first to achieve 'the destruction of the enemy's main forces on the battlefield'. Air-power might attain a direct end by indirect means - hopping over opposition instead of overthrowing it.

The most dangerous error is failure to recognize our own tendency to error.

...regrettable as it may seem to the idealist, the experience of history provides little warrant for the belief that real progress, and the freedom that makes progress possible, lies in unification. For where unification has been able to establish unity of ideas it has usually ended in uniformity, paralysing the growth of new ideas. And where the unification has merely brought about an artificial or imposed unity, its irksomeness has led through discord to disruption.

It is folly to imagine that the aggressive types, whether individuals or nations, can be bought off ... since the payment of danegeld stimulates a demand for more danegeld. But they can be curbed. Their very belief in force makes them more susceptible to the deterrent effect of a formidable opposing force.