"Not simply the greatest but the only truly great book on war," declared historian Bernard Brodie of Principles of War. Written two centuries ago by a Prussian military thinker, this is the most frequently cited, the most controversial, and in many ways, the most modern book on warfare. Author Carl von Clausewitz fought against the armies of the French Revolution and Napoleon, served as a high-ranking staff officer, and became a prominent military educator. By his day, war had become a contest of mass armies, with results decided by swift, concentrated action and superior effort. "Victory is purchased by blood," Clausewitz proclaims, stating that total victory is assured only through annihilation of the enemy's forces. Based on the author's "though and observation, philosophy and experience," Principles of War examines the moral and psychological aspects of warfare, stressing the necessity of such qualities as courage, audacity, and self-sacrifice and the importance of morale and public opinion. Clausewitz emphasises the notion of strategy as an evolving plan, rather then a formula, a concept that makes this work adaptable to modern strategists in fields beyond military science. Translated into virtually every major language, Principles of War is required reading in intermediate-level and senior military schools, as well as in many civilian strategic studies programmes and business schools.