A top secret intelligence analysis written 1919-1920 by the members of Room 40, the British deciphering unit in the Admiralty, never published before. It's a history of the decryption of German naval and diplomatic messages in World War I, about German Uboat warfare and High Sea Fleet actions including the Battle of Jutland 1916.
- Language : English
- Hardcover : 729 pages
- ISBN-10 : 3902433779
- ISBN-13 : 978-3902433770
