It is probably true to say that no land battle of this century passes Cambrai in importance. Up to the winter of 1917 warfare had changed only in degree since the coming of gunpowder. The scenario, with parts for horse, foot and guns, remained essentially the same. All this was part of a world about to disappear for good with the introduction of the tank. The British Army, hammered by years of war and facing almost alone the vastly increasing strength of its enemy, was expected by most observers to be near to going down in defeat. Instead of that, using British designed and built fighting machines of a novel kind, it attacked and drove the Germans from the strongest fortifications ever built. Nobody, save for a dedicated few, had believed such a feat possible. After profiting from its lessons the same Army, 12 months later, achieved its greatest victories of all time and saved Europe, for a time, from German dictatorship. The methods used made obsolete everything that had gone before and laid out the ground for each serious operation of war from Amiens to the Gulf.