Peter M. Grosz had the gift that he could write down complex history in a very readable manner. As he combined this with his systematic research method and German knowledge (his roots were in Germany) it makes that all of the PMG writings happen to be interesting and readable.
He has written an amazing volume of books and magazine articles in about 40 years. His whole collection (books, pictures, handwritings) is now in the Deutsches Technik Museum in Berlin. It might be interesting to have a look. Their (book) catalog can be found
here. AFAIK the pictures cannot be consulted in a digital form via internet, at this time. But it may come, one never knows.
Cheers
Kees