&quot;The Codebreakers&quot; cited above, is a massive history of cryptography. The same author, David Kahn, has written a book focusing on the Enigma called &quot;Seizing the Enigma&quot;.<p><a href="http:&#x2F;&#x2F;www.amazon.com&#x2F;Seizing-Enigma-German-U-Boats-1939-1943&#x2F;dp&#x2F;0395427398&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.amazon.com&#x2F;Seizing-Enigma-German-U-Boats-1939-194...</a>