Although the Royal Navy did not invent the submarine, Norman Friedman’s new book demonstrates how innovative the British were in their submarine design–more so than most realize. Royal Navy submarines performed well in combat in both world wars, and often in unheralded ways. By 1914, Britain had the largest submarine fleet in the world and by the end of World War I some of the largest and most unusual of all submarines–whose origins and design are all detailed in this new book. Heavily illustrated with photos and original plans, this volume, incorporating so much original analysis, will be eagerly awaited by naval historians and enthusiasts everywhere.