Anyone who wants more of a history of WW2 crypto that extends the cast of characters beyond Turing (and the cast was significant and varied) should read "Battle

Anyone who wants more of a history of WW2 crypto that extends the cast of characters beyond Turing (and the cast was significant and varied) should read "Battle of Wits" (http://www.amazon.com/dp/0743217349 http://www.amazon.com/dp/0743217349) the historian who wrote it wrote it after a large NSA declassification in 1996. What's even more extreme about the Polish codebreakers, a story you would read in Battle of Wits, is that they were evacuated from Poland to France after the invasion of Poland, and then stayed in occupied France working in secret for the Allies as part of the occupation government. They posed to the occupation government as the occupation governments signals intelligence system but secretly supplied GC&CS with information they intercepted from the continent (which the Allies had a lot of trouble doing only from the UK). They did that for years, when they tried to evacuate themselves to Spain, a few of them were captured, interrogated, and did not give up the goods about either the invasion or the secret of Enigma. If you want wartime crypto heroes you would have a hard time doing better than Jerzy Różycki, Henryk Zygalski and Marian Rejewski.