4. Cause for Alarm by Eric Ambler

(written Dec 3, 2015 catching up)

Another one from the Intrigue quartert, A Cause for Alarm, stars a young engineer who desperate for work ends up running an arms factory in Italy.  It's a great telling of the naive guy slowly realizing the forces conspiring around him.  The adventure part of the story is a flight across frontiers, which was really cool.  Great book.