The German U-boat campaign came closer to defeating the Allies than any other campaign in World War II. Every aspect of life and work in the U-boat arm is explored in this book, from U-boat design and construction, weaponry, personnel and training, the U-boat commanders and "aces", the infamous Enigma machine, to the development of wolfpack tactics. Full accounts are given of all German U-boat operations, and in all theatres, from convoy hunting in the Atlantic to minelaying in the Channel and North Sea.