A decent addition to the series, but if the previous entries were 5s this is a 3. I found it to be less polished than the previous entries, and a less fulfilling, and the name dropping was silly. Author seems to portray a paranoia not found in his other Frank Sawyer books.
I really enjoyed this book. Though it didn't end as I hoped it would, I'm intrigued and will be looking forward to the next book in the series. I've read the two previous book in the series and while I believe it would be helpful to read Out By Night before reading Without A Shadow I think you could still understand the story just fine reading it as a stand alone.