For four centuries the British realm depended upon sea power to defend its interest and independence against a myriad of threats both military and economic. During this time the Royal Navy established itself as the "Sovereign of the Seas," helping transform England, and later Great Britain, from an unassuming island nation perched on the edge of the European continent to the center of a global empire. Yet the advent of World War II presented Britain's maritime services with their greatest challenge to date. At stake was the survival of the nation.The Longest Campaign tells the story of this epic struggle and the indispensable role that British sea power played in bringing about the victory that shaped the world we live in today. It is a complete, balanced and detailed account of the activities, results and relevance of Britain's maritime effort in the Atlantic and off northwest Europe throughout World War II. It looks at the entire breadth of the maritime conflict, exploring the contribution of all participants including the Royal Navy, Royal Air Force and British merchant marines and their Commonwealth equivalents. It puts the maritime conflict in the context of the overall war effort and shows how the various operations and campaigns were intertwined. Finally, it provides unique analysis of the effectiveness of the British maritime effort and role it played in bringing about the final Allied victory.