Secret codes /

Presents several easy codes with messages to decode and directions for making and writing with invisible ink and devising one's own code.

Bibliographic Details

Main Author:	Fletcher, Helen Jill, 1910-
Other Authors:	Cooper, Michael, 1943-
Format:	Book
Language:	English
Published:	New York : F. Watts, 1980.
Series:	Easy-read activity book.
Subjects:	Ciphers > Juvenile literature. Ciphers.