Secret and urgent : the story of codes and ciphers /

Bibliographic Details
Main Author:	Pratt, Fletcher, 1897-1956
Corporate Author:	American Cryptogram Association
Format:	Book
Language:	English
Published:	Garden City, N.Y. : Blue Ribbon Books, 1942
Subjects:	Ciphers. Cryptography.

by Pratt, Fletcher, 1897-1956
Published 1939

Book