The remarkably effective submarines (U-boats) of the German Navy devastated the Allies during the first part of World War II and very nearly brought British and American sea forces to their knees. Military historian Hoyt here describes the years when U-boat "wolf packs" under the command of Admiral Karl Doenitz terrorized the Allies, sinking a third of Britain's battleships in 1939, and how the Allies came back, developing anti-submarine weapons that sent almost three-fourths of the U-boat crews to the bottom of the ocean. The U-Boat Wars is a gripping account of the battles at sea and the men—Doenitz, Churchill, sub-hunter Captain F. J. Walker, and others—who decided the fate of the Atlantic.