Although this book will be filed under SF because of its alternative history background, it is actually a murder/mystery with its roots in the traditional film noir style.
The lead character Zee Zee/Raf is a mysterious, dangerous and reluctant hero. He is surrounded by powerful people with schemes of their own. There is the inevitable love interest an to cap it all a femme fatale.
Somehow despite the clichés, this is an entertaining book with plenty of charm and engaging (if not exactly deep) characters.
JCG, is also very clever with is background. Many authors would put the alternate history in the foreground and show off their clever concept, but JCG keeps it where it belongs dropping references in from time to time with a reasonable degree of subtlety and a great deal of restraint.
In case you are interested, the alternate history background is that the US didn't join in WWI and that Germany under the Kaiser + the Ottoman empire flourished over the rest if the century.
The novel is set in Alexandria, Egypt and opens (pretty much) with the Zee Zee arriving there from Seattle.
I enjoyed it and would happily recommend it it to anyone who enjoys murder mysteries and/or near future SF.