The authors of the piece on I. F. Stone have a book due to hit the shelves. I could tell you why it is an important book. But i'm just a guy pecking away at a keyboard on the internet. Try this endorsement instead:
So outstandingly authoritative and convincing is this material that it will take an honored place alongside the basic sources on Soviet espionage in the United States. Here, the heart of the KGB is laid out as never before.—Tennent Bagley, author of Spy Wars
That would the Tennent Bagley who wrote the best recent book on CIA and counterintelligence.