Submariners are a special breed. Not for them a life on the ocean wave, the fresh air and sunshine of other naval sailors. With stealth and daring they go deep and dark, alone and unseen, in often dangerous waters. They sometimes call themselves the Silent Service, with good reason. Australian submariners have done extraordinary deeds in the First and Second World Wars and, more recently, the Cold War. In April 1915 the Australian submarine AE2 penetrated the Dardanelles Strait to ' run amuck', a historic feat that was a turning point in the Gallipoli campaign. Eventually captured, her crew spent three harrowing years as prisoners-of-war in Turkey. In the Second World War Australian naval volunteers made their name serving in midget submarines, attacking Hitler's mightiest battleship, the Tirpitz, in the icy waters of a Norwegian fjord. Later, they fought the Japanese in the South China Sea. And in the last half of the twentieth century, RAN submarines played a vital role tracking the Soviet navy in the Pacific Ocean. One wrong move could have led to outright war. The risks they ran, the perils they met and the intelligence they gathered are still classified Top Secret. Submarines and the sailors who serve in them have been and remain the tip of the spear of Australia's defences. For the first time, this is their unique story.