Records show that human beings have been using codes to conceal messages for over 2,000 years! This revealing book traces codes throughout history, from an encryption device used by the Spartans in 400 B.C. to the Enigma Code of the 1940s, pausing to consider coded military secrets and newspaper scoops alike. Students will be delighted by code-cracking diagrams. Illuminating sidebars, primary source documents, and vivid illustrations all add to this...