Singh, Simon. <br/><br/>
The code book :  the secret history of codes and code-making / 
Simon Singh. 
 - London :  Fourth Estate,   1999. 
 - xiii, 402 p. :  ill. ;   20 cm. 
<br/><br/>Includes bibliographical references and index. 
<br/><br/><label>ISBN: </label>9781857028898 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Coding theory.<br/>Cryptography.<br/>Cryptography-- History.
<br/><br/><label>Dewey Class. No.: </label>652.8