Melvyn Bragg and his guests discuss On War, a treatise on the theory and practice of warfare written by the Prussian soldier and intellectual Carl von Clausewitz. First published in 1832, Clausewitz’s magnum opus is commonly regarded as the most important book about military theory ever written. Informed by its author’s experience of fighting against the mighty armies of Napoleon, the work looks not just at the practicalities of warfare, but offers a subtle philosophical analysis of the nature of war and its relationship with politics. Notions such as the Clausewitzian Trinity have had an enormous effect on later military leaders. But its influence is felt today not just on the battlefield but also in politics and business.