The First World War was one of the costliest conflicts in history, much of it fought over a narrow and bloody swathe of France and Flanders. At the outbreak of war, it was anticipated that conventional battle would bring a quick resolution, but four years later, strategy, tactics and the material of war had changed almost beyond recognition. For most of that time, the two sides had been locked in the stalemate of trench warfare, a battle conducted along a Western Front of over 400 miles, in which almost 3 million men were killed. In this anniversary edition, World War I trench expert Stephen Bull provides a complete picture of trench warfare on the Western Front, from the construction of the trenches and their different types.