Singh, Simon <br/><br/>
The code book: the secret history of codes and codebreaking   the secret history of codes and codebreaking  
Simon Singh 
 - Paperback ed. 
 - London :  Fourth estate,  2000. 
 - 402 p. :  ill. 
<br/><br/><label>ISBN: </label>1-85702-889-9 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Cryptography--History.
<br/><br/><label>Dewey Class. No.: </label>652.8