U-boat hunters : code breakers, divers and the defeat of the U-boats, 1914-1918
Robert M. Grant (Author)
"In this book, the author explains how the code breakers at the Admiralty's Room 40 were able to break into the German naval codes during the First World War."--Jacket
Print Book, English, 2003
Naval Institute Press, Annapolis, Maryland, 2003