Top Secret: A Handbook of Codes, Ciphers and Secret Writing

"The author's upbeat, positive tone is refreshing and his enthusiasm about his topic is contagious." — SCHOOL LIBRARY JOURNAL (starred review)Pssst! Do you know the difference between a code and a cipher? Can you tell a St. Cyr slide from a Cardano grille? Did you know that the discovery of a substitution cipher caused Mary Queen of Scots to...