A thriller unlike any other I’ve ever read—because it all was true, with the world at stake. The French created an alliance before WWII, between X (Paris), Y (London, and Z (Warsaw) to share knowledge to break and continue breaking the Enigma cipher each time the Nazis improved it. Breathtaking were the risks taken by the Pole code breakers, the French super-spy, and the German super-spy stealing his country’s secrets. Truly nerves of steel. It’s hard to have complaints about such an amazing book—and they are wholly my own problems. The spies had many names, so it was very hard to keep track of who was who. And the author, Alan Turing’s nephew, is clearly brilliant explaining in detail how each iteration of the Enigma machines worked and how each time the code-breakers broke them, sometimes with cardboard mock-ups of the machines. I couldn’t follow the technical details to save my life. But I just took it all in stride because the real-life story going on was so awe-inspiring. Strongly recommended. ( )

The fascinating story of how the Polish, French and British intelligence services collaborated (fitfully) in the breaking of the Enigma code. Goes back to the origins of work on Enigma in the 1920s and how it was gradually made more difficult to break by the Germans. Sir Dermot does his best as a non-engineer to explain how the machines worked and how permutation theory enabled code-breaking, but I'm afraid this was beyond me. Very little about the role of Alan Turing which Sir Dermot has written on elsewhere.

Alan Turing's nephew's history of the decipherment of the Enigma coding machine focuses more on the work by a team of Poles breaking earlier versions of the Enigma codes. It does assume rather more familiarity with how the physical machines actually work than I possess, which made it hard to follow in places, but it was nevertheless fascinating. ( )