“Perfect Spy”:http://www.amazon.com/Perfect-Spy-Incredible-Vietnamese-Communist/dp/0060888385 by Larry Berman.
A really good book about the life of Pham Xuan An, arguably one of the best spy in modern history. The book gave some good inside about his life and Saigon social atmosphere during the war. The Author tried to project An as a nationalist supported the Communist movement for his love of an independent Vietnam not for the ideology, which is probably true.
However, to understand the politic dynamic of the war, this is not a good book to read. This book, regardless of many opinions in Amazon saying it is anti-American, follows quite closely with the mainstream Western media framework. A better treatment of the war on media and political aspects is “Manufacturing Consent”:http://www.amazon.com/Manufacturing-Consent-Edward-S-Herman/dp/0099533111/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1196582985&sr=1-1, to have a good view about military aspect of the war, you can check out “Bright Shining Lie”:http://www.amazon.com/Bright-Shining-Lie-America-Vietnam/dp/0679724141/ref=pd_bbs_2?ie=UTF8&s=books&qid=1196583169&sr=1-2.
Overall, this a very good book about life of a “perfect” spy.