Enigma:

In 1933, three Polish mathematicians led by Marian Rejewski succeeded in breaking the German Enigma cipher, which the Germans considered unbreakable. In 1939, just before the outbreak of the war, the powerful British decoding operation at Bletchley Park, which supplied vital intelligence services. This text off ers a concise, up-to-date history of the Enigma decryption in Poland and the use of this achievement in Poland and England. Over 60 black-and-white illustrations enrich in the text.