War is the realm of uncertainty; three quarters of the factors on which action is based are wrapped in a fog of greater or lesser uncertainty.
Carl von ClausewitzThere is nothing more common than to find considerations of supply affecting the strategic lines of a campaign and a war.
Carl von ClausewitzFriction is the only concept that more or less corresponds to the factors that distinguish real war from war on paper.
Carl von ClausewitzIf we do not learn to regard a war, and the separate campaigns of which it is composed, as a chain of linked engagements each leading to the next, but instead succumb to the idea that the capture of certain geographical points or the seizure of undefended provinces are of value in themselves, we are liable to regard them as windfall profits.
Carl von Clausewitz