Friction is the only concept that more or less corresponds to the factors that distinguish real war from war on paper.

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.

Architects and painters know precisely what they are about as long as they deal with material phenomena.... But when they come to the aesthetics of their work, when they aim at a particular effect on the mind or on the senses, the rules dissolve into nothing but vague ideas.

Whenever armed forces . . . are used, the idea of combat must be present. . . . The end for which a soldier is recruited, clothed, armed, and trained, the whole object of his sleeping, eating, drinking, and marching is simply that he should fight at the right place and the right time.

Many intelligence reports in war are contradictory; even more are false, and most are uncertain.

I shall proceed from the simple to the complex. But in war more than in any other subject we must begin by looking at the nature of the whole; for here more than elsewhere the part and the whole must always be thought of together.

The more a leader is in the habit of demanding from his men, the surer he will be that his demands will be answered.