Introduction

'War is merely the continuation of policy by other means.' This famous sentence from the first chapter of On War is the heart of the book. Clausewitz offers no formulas or rules for fighting; he tries to understand the nature of war. War, he says, is an act of violence to compel the enemy to do our will, and in theory tends to extremes; but real war is always constrained by its political purpose. War is a 'remarkable trinity' of violence and hatred, chance and probability, and policy and reason. He introduces the ideas of the 'fog of war' and of 'friction': in war everything is very simple, but the simplest thing is difficult. He also discusses attack and defence, military genius, moral forces and the decisive battle. It is the most important work of military theory in the West, and with Sun Tzu's Art of War it forms the twin peak of military thought East and West. This volume translates its most important parts.