The world has a way of undermining complex plans. This is particularly true in fast moving environments. A fast moving environment can evolve more quickly than a complex plan can be adapted to it. By the time you have adapted, the target has changed.

Men are always more inclined to pitch their estimate of the enemy's strength too high than too low, such is human nature.

War is a conflict of great interests which is settled by bloodshed, and only in that is it different from others.

All war presupposes human weakness and seeks to exploit it.

If you entrench yourself behind strong fortifications, you compel the enemy seek a solution elsewhere.

War is only caused through the political intercourse of governments and nations - war is nothing but a continuation of political intercourse with an admixture of other means.

War is regarded as nothing but the continuation of state policy with other means.