Fun with Secret Writing (Dover Children's Activity Books)

Fascinating, easy-to-understand book for would-be cryptanalysts of all ages teaches how to invent and decipher a host of codes and secret messages, including the "Moving Ahead" cipher used by Julius Caesar; dots and pinpricks, as used by the secret Rosicrucian society; and even a system used by Sherlock Holmes. 14 black-and-white illustrations.