The U-Boat: The Evolution and Technical History of German Submarines (Repost)

It's the enthusiast's bible of U-boat history and development, with more detail and technical information than any other book on the subject. Displaying photographic coverage second to none, it has a wealth of submarine plans and profiles that illustrate every aspect of design and operation. Track the constant improvements implemented from World War I to World War II and beyond: the single-drive models, small and midget versions, the move to high submerge speed, the change to Type XXI and XXIII constructions, and production in the twilight of Nazi defeat.