Carl von Clausewitz

War is not merely a political act but a real political instrument, a continuation of political intercourse, a carrying out of the same by other means.

The more a general is accustomed to place heavy demands on his soldiers, the more he can depend on their response.

War is the province of danger.

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

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

War is the domain of physical exertion and suffering.