Nearest Exit by Olen Steinhauer

Nearest Exit, the sequel to the Tourist is just as fascinating and fast-paced. Milo Weaver is back on the job after a short jail term. Back to the murky world of the tourist (a black-ops branch of the CIA). However, he now has a wife and daughter and mixed feelings about his work. Before he is taken back into the fold he must prove his loyalty. When faced with murdering a 15 year old girl he balks. Trying to reestablish himself, save the girl, and complete the other assignments makes him realilze he may not be the perfect spy anymore.

Tensions rise when a defector knows everything about the tourists (spies) and states that there is a "mole" in Tourism. Milo realizes his assignment will include saving himself as well as the other tourists.

Olen Steinhauer writes with the same power about modern day spying as John Le Carre did during the Cold War.