Interesting.

I ran across a book called "The Persecution of the Catholic Church in the Third Reich." Since it claimed to have been published in 1941, I purchased it as primary textual material.

After I received it, I wondered where it came from because the author is anonymous.

A little internet research turned up this:

2. The Persecution of the Catholic Church in the Third Reich (1942).

It was published in London during 1942 and the author’s identity had, at the time, to be kept secret. Copies and reprints are available on the Internet and seem to vary between £5 - 18 or $9 - 25 plus delivery.

This book, of 565 tightly printed pages, is full of detailed events and is indispensable to anyone researching this subject.

After the war the history of the book’s formation could be revealed. Admiral Canaris was a German hero during the First World War and very patriotic. In 1935, when the army was still free from close Nazi control, Canaris was appointed head of the Army Forces Intelligence Service – the Abwehr.

Canaris (a non-practising Catholic) organised a secret group within the Abwehr, which included Josef Muller, a dedicated Catholic. So Muller, while travelling widely on secret army work, was able to collect details of persecution without raising Nazi suspicions. When completed, he delivered the information to the Vatican where Fr. Walter Mariaux translated and organised the material. In 1941 he passed the typescript to ‘Burns and Oates’, a Catholic publisher in London. They published it in 1942.

The Canaris group were involved in an assassination attempt on Hitler’s life, to be followed by an army seizure of power. On July 20th 1944, Colonel Von Stauffenberg, another dedicated Catholic, planted a bomb close to Hitler, but he was not killed. Most of the group, including Canaris, were exposed and executed, but Muller managed to remain free.//

After reading many books on the Catholic Church under the Nazis, I had never heard that any such book existed.

Another interesting factoid - Pius XII acted as the personal conduit for meetings between the British and and the German resistance that involved Canaris.

I knew about that, but I hadn't realized that there was more information floating through that conduit.