Title: Action This Day
First published: 2001
Subjects: World War, 1939-1945, Cryptography, Electronic intelligence, Secret service, Great Britain. Government Communications Headquarters, Great Britain, History, Intelligence service, Guerre mondiale, 1939-1945, Renseignement électronique, Cryptographie, Histoire, Enigma, Dechiffrierung, Geheimschrift, Government publications, great britain, World war, 1939-1945, cryptography, World war, 1939-1945, secret service, great britain