World War II was only a few hours old when the Battle of the Atlantic, the longest campaign of the Second World War and the most complex submarine war in history, began with the sinking of the unarmed passenger liner Athenia by the German submarine U30. Based on the mastery of the latest research and written from a mid-Atlantic – rather than the traditional Anglo-centric – perspective, Marc Milner focuses on the confrontation between opposing forces and the attacks on Allied shipping that lay at the heart of the six-year struggle. Against the backdrop of the battle for the Atlantic lifeline he charts the fascinating development of U-boats and the techniques used by the Allies to suppress and destroy these stealth weapons.