ABSTRACT
Knowledge of the terrain is basic to all military activity and its understanding can make the difference between victory and defeat. Its discriminating use has been the hallmark of great commanders, allowing 300 Spartans to hold the Persian army at bay in the narrow defile of Thermopylae, the Black Prince to gain success at Poitiers by pushing forward his light troops on to ground too soft for the French armour, and Wellington to screen his main dispositions at Waterloo. With the advent of gunpowder, questions of cover and the intervisibility of sites gained importance. Since 1914, the vastly increased mobility of armies, the expanded range and destructiveness of projectiles and, above all, the use of air power have transformed warfare. This has altered, but not removed, its dependence on the nature and configuration of the ground surface.
