The Hidden World

Author: Haldane, R. A.
Publisher: Robert Hale
Place: London
Cover: dust jacket
Condition: Very Good
Category: Intelligence & Espionage
Year: 1976
Edition: 1st edition
Size: octavo
Description: 207pp., bibliog., index, The Story of Hidden Writing from the Earliest Times. How ciphers and Codes work and how they are unravelled. How the Arabs discovered the constancy of letter frequencies and their remarkable forms of invisible ink. Also how the BBC broadcast in code in WWII