Yesterday evening all old books in my local chess club were auctioned. I was able to get some bargains, as one of the books was written by Gerhart Gunderam, a name that is familiar to many Blackmar Diemer gambiteers. I bought the book for 1 euro and indeed - the book is loaded with lots of games and analysis on the Blackmar Diemer. The is dated 1961 and is signed, unfortunately not by the author. It is like holding history in my hands as I was still like that one.
I will start looking into it and report any interesting stuff back to you asap.