The best way to learn about the German codebreakers is to read the original reports of the postwar interrogations of German personnel.Especially valuable are Allied reports covering the security of their communications as they have already filtered this information.
So how can you get hold of Ticom reports ? The ones released in the public archives are hard to find.
I can speak with authority about the files found in the British archives.They are in collection
HW 40 - ''Government Code and Cypher School: Security of Allied Cyphers Section: Security Files on Allied World War II Communications'' .
Specifically files titled ''German Army Y Service'' , '' Y Service of the OKW '' , ''German Air Force Y Service'' .
Let me be even more specific : 180-81 Pers Z , 186 Forschungsamt , 166-9 OKH/GdNA , 182-4 B-Dienst , 160-3 GAF agency , 172-4 OKW/Chi.
A very detailed report on the British Naval Codes and Ciphers as well as the German efforts against them can be found in ADM 1/27186 '' Review of security of naval codes and cyphers 1939-1945''.Many thanks to Phil Gollin for posting a summary of this report here .
Keep in mind that some files have parts retained.
I'd also like to add that my researcher is Dr Kevin Jones - KLJ Historical Research ( KLJ-Research@hotmail.co.uk ) .I am completely satisfied with his work.