If you like Alan Furst you need to give David Downing a read...fast-paced, atmospheric...having visited Berlin shortly after the Wall came down, Downing's descriptions made me feel like I was back in the city.
I would definitely recommend this book to anyone interested in espionage or Germany during the lead up to WWII.
Buy this book at:
http://www.powells.com/biblio/71-9781569479711-0