This is a nice history of a Cold War catastrophe. Philby was a Soviet spy and a top official in MI6, England's Secret Intelligence Service. He duped them and the CIA for 20 years. The book is a little more history than I was expecting. I was hoping for some description of MI6 tradecraft, which this book doesn't really provide. But if you like spy novels and are interested in the intelligence field, this book serves as useful background. Recommended.