The Tristan Betrayal: Robert Ludlum

This was a fast paced globe trotting novel. An American spy during WWII is one of the best in the operation and avoids death while getting into just enough trouble to be convincing. His boss sends him back to Moscow after his cover is blown in France. He rekindles a relationship with a Russian Ballerina that he had fallen in love with 6 years earlier. She never tells him they have a son even when she goes to her death. The spy uses her to send forged documents to her Nazi boyfriend in an effort to get German to invade Russia. She understands that she has to be found as a traitor in order for the documents to seem real. She does this for her country, for the man she loves, and so her son will live in a better world.