"Under the four oceans and the seven seas, American and Soviet submarines fight a near-war every day of the year. Relentlessly, they search for one another, trailing an adversary when they can and trying to evade one when detected. They make every move of a real war, except shoot. ... Should a shooting war erupt, many experts argue, submarines would be the capital ships of the American and Soviet fleets. The battleship dominated naval operations in World War I, and the aircraft carrier brought victory at sea in World War II, but the nuclear-powered submarine would provide the edge in a future conflict."