I found this story to be well written and interesting. The storyline was, in fact, historical albeit about 10 years prior to the actual events. I think the story actually makes better history that the real timeline we all know from history.
The author chose to write a story with an implausible plot - the stopping of the Nazi Party prior to them even coming into power. We all know that, unfortunately, the Nazi Party did come into power. That reality kept me from getting "into" the story. Perhaps a storyline in which the Nazi's lose BUT the communists take over and then a fictional ending to the novel of what might have happened if the reds had become the governing party in the 1930's Germany.
One reviewer mentioned that the reader should play the soundtrack to Cabaret in the background. I wish I had thought of that as it would have been a great way to read this book.
I look forward to another novel by Paul Grossman.