On War

Clausewitz served in the Prussian army through the Napoleonic wars and wrote On War over twelve years without completing the revision. His widow published it after his death in 1831, which is why the text is uneven and why some sections contradict others.

The central proposition is that war is a continuation of policy by other means, which establishes that military action has no logic of its own and must be governed by the political purpose it serves. Everything else follows from this. The military objective, the resources committed and the definition of success are all political questions rather than military ones.

His second major concept is friction, meaning the accumulation of small difficulties that make even simple things difficult in war. Weather, exhaustion, misunderstood orders, delayed information and chance combine so that the difference between plans and execution is systematic rather than occasional. His related concept, the fog of war, describes decision-making with incomplete and incorrect information as the normal condition.

He also develops the concept of the culminating point of victory, beyond which continued advance weakens the attacker; the centre of gravity, meaning the source of an opponent's power against which effort should be concentrated; the superiority of defence as a form of war; and the trinity of the government, the army and the people, whose relationship determines what any state can sustain. The text is difficult, contradictory in places and reflects nineteenth-century warfare. The business applications are frequently superficial. The concepts of friction, the culminating point and the primacy of purpose over method transfer directly.