It is axiomatic in modern affairs that any severe or prolonged confrontation will sooner or later see the appearance of armour - if only to guard a striketorn factory or cow an unruly mob. Yet the tank is best at fighting other tanks in a battle of manoeuvre, breakthrough and encirclement. Spitting fiery streaks of death from their machine guns, hurling bolts of destruction from their main guns, crushing obstacles beneath their treads, shrugging off storms of counterfire, tanks have rumbled through the twentieth century like beasts from another age. On land, they are the supreme threat, a tool of war whose speed, firepower, and steel-clad massiveness can hurt in many ways - by punching into rear areas and destroying command posts or supply depots, by rolling over a dug-in enemy, by moving swiftly to cut off an avenue of retreat, or simply by spreading a morale-sapping chill of dread.