Examines a number of different ways of writing secret messages, including invisible ink and a variety of ciphers. Gives suggestions and aids for code-breaking.
Contents
Moving ahead -- Using a key letter -- Five-letter words -- Secrets of a bishop -- Around and around -- Secrecy in numbers -- Dots and pinpricks -- Ticktacktoe cipher -- Open spaces -- Crossword grill -- Pretty patterns -- Revolving circle -- Secret inks -- Code-breaking -- Aids to code-breaking -- Practice activities.
