Secret codes
By: by Helen Jill Fletcher ; illustrated by Michael Cooper.
Contributors: Cooper, Michael, 1943-
Series: An Easy-read activity book
Publisher: F. Watts
Published: 1980
Place of publication: New York
Language: eng
Number of pages: 32
Subjects: Ciphers -- Juvenile literature.; Ciphers.
Description: Presents several easy codes with messages to decode and directions for making and writing with invisible ink and devising one's own code.