"The Codebreakers" cited above, is a massive history of cryptography. The same author, David Kahn, has written a book focusing on the Enigma called "Seizing the

"The Codebreakers" cited above, is a massive history of cryptography. The same author, David Kahn, has written a book focusing on the Enigma called "Seizing the Enigma". http://www.amazon.com/Seizing-Enigma-German-U-Boats-1939-1943/dp/0395427398/ http://www.amazon.com/Seizing-Enigma-German-U-Boats-1939-194...