On War by Carl von Clausewitz was first published in Germany after the Napoleonic Wars. One of the most significant treatises on military strategy ever written, it is still prescribed at various military academies today. Its description of 'absolute war' and its insistence on the centrality of battle to war have been blamed for the level of destruction involved in both the First and Second World Wars.

Hew Strachan's accessible book challenges the popular misconceptions that surround On War. He dispels the notion that for Clausewitz policy necessarily shapes war, asserting instead that war has its own dynamic and that its reciprocal effects can themselves shape policy. Strachan returns to the very heart of On War to recover the arguments at its core; in the process challenging the received wisdom about this cornerstone of military strategy.