This book describes the operations of a group of Italian submarines that took part in the Atlantic conflict during the World War Two. A total of 32 submarines flying the tricolour flag of the Regia Marina passed through the Betasom base, located at the French port of Bordeaux. Almost two hundred of their combat patrols are presented in detail, all victories and defeats being discussed. The work also covers the story of the base itself, the doctrine of Italian submarines, biographies of commanders, submarines and other factors influencing successes and failures. The Italians commenced their operations in the Atlantic badly, due to a lack of previous experience they turned out to be unprepared for the actions that awaited them, but with stubbornness and hard work, they managed to transform their Atlantic contingent into a very effective fighting machine. Thanks in large part due to the efforts of Betasom’s personnel, the Italian Navy can be proud of being the sixth most effective submarine fleet in the history of this type of weapon. A separate chapter presents the history of the Italian blockade runners, which, based in Bordeaux, were to break into the Far East, carrying in both directions material of strategic importance, urgently needed for the war-fighting of Italy, Germany and Japan.