I am currently reading a book titled:
KGB THE INSIDE STORY by Christopher Andrew & Oleg Gordievsky.
This book rocks man. It is kind of a long read and maybe a little too wordy for some but it is like a complete look into the KGB from its inception as a Tsarist intel unit to the height of cold war paranoia.
The Oleg Gordievsky guy was head of the London KGB residency, and was a full Colonel before he defected so it is not all just speculation and contrivances.
It is published by Harper Collins, and the ISBN# is 0-06-016605-3
I highly recommend it is a good read and alot of stuff that will really amaze you. We all know that the Stalin was a whacko, but Jeezy petes, theres some stuff in this book that is news to me. he was way over the edge.