Codes, Ciphers and Secret Writing

Learn to use the most important codes and methods of secret communication in use since ancient times. Cipher and decipher codes used by spies. Explore the famous codes that changed the fate of nations and political leaders. And enjoy hours of fun experimenting with cryptography ― the science of secret writing.
Beginning with simple letter substitutions and transposition ciphers, world-famous science writer Martin Gardner explains how to break complicated polyalphabetical ciphers and codes worked with grids, squares, triangles, and charts. You'll learn codes that are keyed to typewriters and telephone dials . . . even codes that use playing cards, knots, and swizzle sticks. Experiment with invisible writing ― inks that glow in black light and turn red under heat ― and explore the possibilities of sending messages through outer space to unknown worlds.