Over 2,500 submarines saw action during WWII from all combatant nations, and for the first time all classes and types of submarines are covered in a single book. From midgets to large U-cruisers, along with projected and experimental designs, a mass of detail records technical characteristics for each class of submarine. Exhaustive charts and hundreds of valuable photos tell the facts and figures about construction, displacement, dimensions, speed, range, operational depth, fuel load, armament, and complement. Each submarine's performance is chronicled, including the fate of each member of the class. An outline of the evolution of the submarine and the development of submarine warfare offers a rare view of the role of design improvement in the outcome of the war.