Operation Whisper

The neighbors next door--how much do you really know about them? For all you know, they could be just who they say they are. On the other hand, they could be, they just might be, spies. 

Turns out, that's exactly who Morris and Lona Cohen were, operating deep under cover for years both in the United States and in Great Britain.

Very well written, Carr's book made me think twice about what motivates people to betray the very same countries to which they owed so much.