[edwest2]

https://www.amazon.de/G%C3%B6rings-N.../dp/3957681944

I found the following to be a bit surprising.

"It was the largest intelligence service of the Nazis. Although the "Ministry of Research" of the Ministry of Aviation - as the name implied - was run by Hermann Goering as a private service, it resided in the middle of Berlin, and it was unknown not only to the German population but also to the Allies. Göring's listener, supported by the German Reichspost, did an excellent job. In peace and war they read hostile radio communications and listened to foreign governments and diplomats as well as German Nazi opponents. Even US President Franklin D. Roosevelt and British Prime Minister Winston Churchill were intercepted.

"In total, at least half a million conversations were overheard and partially recorded - at a time when there were far fewer phone lines than today and the people to be monitored were deliberately chosen, a tremendous number. Equipped with state-of-the-art technology and constantly competing with comparable other Nazi institutions, Adolf Hitler provided important foreign policy information, which he specifically used. For Hermann Göring, it was a very important instrument, much underrated today, for expanding his personal power. Although the once huge files were destroyed in the last months of World War II, the book provides an exciting and enlightening insight into the history of the Research Office."