How to Write Codes and Send Secret Messages
Explains how to write and decipher space codes, hidden word codes, and alphabet codes and gives formulas for invisible ink. Includes suggestions for delivering coded messages.
Materias
Ediciones (2)
- How to Write Codes and Send Secret Messages (1973)
Scholastic Paperbacks · inglés · ISBN 9780590026062
- How to write codes and send secret messages (1970)
Four Winds Press · inglés
