The art of the indirect approach can only be mastered, and its full scope appreciated, by study of and reflection upon the whole history of war. But we can at least crystallize the lessons into two simple maxims- one negative, the other positive. The first is that, in face of the overwhelming evidence of history, no general is justified in launching his troops to a direct attack upon an enemy firmly in position. The second, that instead of seeking to upset the enemy's equilibrium by one's attack, it must be upset before a real attack is, or can be successfully launched
B. H. Liddell HartIn a campaign against more than one state or army, it is more fruitful to concentrate first against the weaker partner than to attempt the overthrow of the stronger in the belief that the latter's defeat will automatically involve the collapse of the others.
B. H. Liddell HartIn should be the duty of every soldier to reflect on the experiences of the past, in the endeavor to discover improvements, in his particular sphere of action, which are practicable in the immediate future.
B. H. Liddell HartThe more closely [the German army] converged on [Stalingrad], the narrower became their scope for tactical manoeuvre as a lever in loosening resistance. By contrast, the narrowing of the frontage made it easier for the defender to switch his local reserves to any threatened point on the defensive arc.
B. H. Liddell HartThe easiest and quickest path into the esteem of traditional military authorities is by the appeal to the eye, rather than to the mind. The `polish and pipeclay' school is not yet extinct, and it is easier for the mediocre intelligence to become an authority on buttons, than on tactics.
B. H. Liddell Hart