Hitler's U-boat fortresses

"The French naval bases at St. Nazaire and Lorient, occupied by the Germans in June 1940, quickly became the homes of massive U-boat fortresses - nearly indestructible submarine pens, built by mostly slave labor. From these bases, the U-boats struck merchant shipping at will from the Mediterranean to the North Sea. Thousands of vessels were lost, along with vital war material destined for Britain and the Soviet Union. As a result, the Royal Air Force began an all-out bombardment of the two ports. "Despite their extensive efforts - and those of the Americans who joined them in 1942 - the fortresses would survive, surrounded by the decimated French towns and countryside. This is the story of what was, perhaps, the longest ongoing battle in Europe during the Second World War, seen through the eyes of someone who experienced much of it firsthand."--Jacket.