The great nineteenth-century Prussian general Field Marshal Helmuth von Moltke, ‘The Elder’, once declared that no operations plan survives contact with the enemy. But no one has suggested – least of all Moltke – that an army or a commander contemplating a military operation should have no plan. The same can be said about previous experience of war. A new war is likely to have such a different shape and character from the previous one that previous experience might be found to be of no value or, indeed, even misleading. Army commanders are often accused of preparing for the past war rather than the future one. But no one has suggested that previous wartime experience is not valuable in an army about to embark on a new war.