The study of the American journalist and historian Clay Blair covers the period from the fall of 1942 to May 1945. It was then that the string of brilliant victories of the German submarine forces, according to many historians, who almost put the Allied merchant shipping on the brink of disaster, suddenly ended, replaced by a chain of brutal defeats. And these defeats did not stop until the moment of the final surrender of Germany. But who won the Battle of Atlantic - the British and American cryptographers who decrypted the secret radio codes of the Kriegsmarine, or the Allies' many times superior sea and air power? Giving the most detailed and vivid picture of the German underwater campaign in the Atlantic, the author of this work provides the reader with the opportunity to draw his own conclusion.