Knight Book of Secret Codes (Knight Books)
By Falcon Travis.
Description
Enjoy exchanging secret messages with friends. The reader can learn about poly-alpha ciphers, code grills, symbols, acrostics, invisible inks and special code words. The book includes a section on codes and ciphers in games and contests, and one on how to be a code-breaker. - from Amzon
ISBN(s)
0340197781, 9780340197783
