Civilization might have been spared much of the damage suffered in the world wars this century if the influence of Clausewitz's On War had been blended with and balanced by a knowledge of Sun-tzu's The Art of Warfare. --B.H. Liddel HartFor two thousand years, Sun-tzu's The Art of Warfare was the indispensable volume of warcraft. Although his work is the first known analysis of war and warfare, Sun-tzu struck upon a thoroughly modern concept: "The supreme art of war is to subdue the enemy without fighting."    Karl von Clausewitz, the canny military theorist who famously declared that war is a continuation of politics by other means, also claims paternity of the notion "total war."  His is the magnum opus of the era of the French Revolution and the Napoleonic vars.Now these two great military minds are made to share the same tent, metaphorically speaking, in The Book of War. What a bivouac it is, and what a conversation into the night.Military writer Ralph Peters has written a new Introduction for this Modern Library edition.