Simon Singh <br/><br/>
The Code Book :  The Secret History of Codes and Codebreaking 

 - 1st 
 - London ;  Fourth Estate  1999 
 - 402 p.;  pbk. 
<br/><br/><label>ISBN: </label>9780007453085 
<br/><br/><label>Dewey Class. No.: </label>652.8