01174cam a2200325 4500 130146254 TxAuBib 20120726120000.0 100525s2011||||||||||||||||||||||||eng|u 2009052597 9781410939272 1410939278 (OCoLC)496594405 DLC DLC MnManCP TxAuBib Colson, Mary. Destroy after reading [JN] : the world of secret codes / Mary Colson. Chicago, IL : Raintree, 2011. 32 p. : ill. (chiefly col. ; 25 cm. Culture in action Includes index and glossary. Includes bibliographic references. What's so special about secret codes? -- Early codes -- Code symbols and cracking codes -- Code school and the enigma machine -- Coding languages -- Codes of today and tomorrow. 20120726. Cryptography. Cryptography. History. Ciphers. Ciphers. History. Culture in action. TXGPL