At the beginning of World War II, submarine captains were notorious for their lack of initiative. Then a new generation of officers took command. These men and their crews championed a new kind of war, marked by daring risk-taking and methods that were brutal but highly effective. Leading the way in the Pacific was the United States submarine Wahoo, long recognised as the best at its harsh business. Based on extensive research - including newly declassified files, Japanese sources, and the author's long-time correspondence with veterans - Unrestricted Warfare chronicles how a group of junior officers catapulted a submarine force from an ineffective auxiliary body to one of the most lethal instruments of the war