Ever wondered how to make and crack codes and ciphers? Herbie Brennan's essential guide contains everything a serious cryptographer and code-buster needs, including: codebreaking methods, examples and tests; how to develop complex ciphers; tools for encrypting messages, from invisible ink to computer pixels; and, a history of how codes and ciphers have developed, taking in the ancient Greeks, the Kama Sutra, the Enigma machine and computer ciphers.