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 HartThe unexpected cannot guarantee success, but it guarantees the best chance of success.
B. H. Liddell HartThe most consistently successful commanders, when faced by an enemy in a position that was strong naturally or materially, have hardly ever tackled it in a direct way. And when, under pressure of circumstances, they have risked a direct attack, the result has commonly been to blot their record with a failure.
B. H. Liddell HartIt 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.
B. H. Liddell HartThe predominance of moral factors in all military decisions. On them constantly turns the issue of war and battle. In the history of war they form the more constant factors, changing only in degree, whereas the physical factors are different in almost every war and every military situation.
B. H. Liddell Hart