Codes, ciphers and secret writing
By: George Beal ; illustrated by  Jenny Thorne and Oxford Illustrators Ltd.
Contributors: Thorne, Jenny.
Publisher: Treasure Press
Published: 1990
Place of publication: London
Language: eng
Number of pages: 77
Notes: Originally published as "Codes, ciphers and secret writing": London:  Hamlyn, 1973.

Index.