Silent Warfare: Understanding the World of Intelligence, 3d Edition Book

I got interested in intelligence while visiting the sites of D-Day. What a fascinating history! During WWII, the British had the XX-System and with their "disinformation" broadcasts, they undermined the Abwehr (the German secret service) from the inside. Thus, the Germans were convinced the Allied would attack from Calais and that Normandy was "just" a diversion.

However, after having read this book, I discovered that the XX-System was perhaps the last success of British intelligence. Even if I was never under the impression that James Bond is in any way realistic as a spy, I had no idea that the failures of MI6 were so huge and that so many double agents worked undetected for years. Apart form the infamous Kim Philby, I learnt about George Blake, who should be even more infamous and who's still alive and well, living in Mother Russia after having betrayed his country and caused many deaths.

Also noticeable the CIA and FBI failures. The CIA mole was a guy named Ames, described as a "Philandering, alcoholic underachiever", but nevertheless left free to break havoc for years. FBI bad guy was Hanssen. Both Ames and Hanssen are incarcerated for life, while Blake managed to escape from prison (another British failure...)

Apart from the occasional example of what may go wrong - and it is A LOT - this book is mostly a very technical and very well written manual of how intelligence is organised and what is important, with some interesting insight on the uneasy relation intelligence-politics.