Librería Samer Atenea
Librería Aciertas (Toledo)
Kálamo Books
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Donde los libros
Librería Kolima (Madrid)
Librería Proteo (Málaga)
This book, first published in 1986 and an essential study of signals intelligence, examines Tsarist codebreakers and cryptanalysis during the Weimar Republic; the history of the Government Code and Cypher School; the Ultra programme; hand cyphers and wartime sigint; and surveillance under the Vichy regime.