"A fascinating, challenging book." - A. L. A. Booklist. Experiment with cryptography - the science of secret writing. Cipher and decipher codes: transposition and polyalphabetical ciphers, famous codes, typewriter and telephone codes, codes that use playing cards, knots, and swizzle sticks...even invisible writing and sending messages through outer space. Hours of intrigue and challenge. 45 diagrams.
Introduction
1. Easy Transposition Ciphers
2. Easy Substitution Ciphers
3. How to Break Substitution Ciphers
4. Hard-to-break Polyalphabetic Ciphers
5. Simple Code Machines
6. Invisible Writing
7. Bizarre Methods of Message Sending
8. Codes for Other Worlds
References for Further Reading
