On War is one of the most important books ever written on the subject of war. Clausewitz, a Prussian officer who fought against the French during the Napoleonic Wars, sought to understand and analyze the phenomenon of war so that future leaders could conduct and win conflicts more effectively. He studied the human and social factors that affect outcomes, as well as the tactical and technological ones. He understood that war was a weapon of government, and that political purpose, chance, and enmity combine to shape its dynamics.