Comment War Secrets in the Ether (Score 2) 102
If you're interested in the German side of world war cryptanalysis, an excellent book is War Secrets in the Ether, by Wilhelm Flicke. The author was a German cryptanalyst during the two world wars, and it was written shortly after the end of the second world war. (It is out of print, so I suggest looking in libraries.)
It has been a decade or more since I read it, so I may have misremembered details, but here are a few points of note:
Pre-war, he'd been analysing Russian radio usage. They had a complicated system where the same station would use different call signs depending who they were talking to. This made their intercepts more chaotic and harder to do traffic analysis on. He and all his colleagues were shifted to the western front with the outbreak of war. When the war with Russia started, in the initial shock their complicated system failed and they fell back on a more standard system. Once they started to get over the initial attack and reorganize, they returned to the complicated system. The German cryptanalysts who were present had no experience with this (the experienced ones having been moved) so they interpreted the chaoticness of the signals as showing the Russians were in complete disarray, when the exact opposite was true.
He thought that the course of Battle of Crete indicated that the allies had broken the German codes at that time. (Which was correct, but he missed that they'd broken most of the German codes for almost the entire war.)
They knew that the allies had very good intelligence, but thought that it was supplied by spies. As a result, he spend the second half of the war on a whack-a-mole mission to shut down spy radio transmitters.
He complained about the multitude of German intelligence agencies and their lack of cooperation due to infighting.