Have read both books - this one and the written by O.G. Both are similar but both are worth reading. Well written and so revealing about the hidden world of spy craft which the common citizen on the street never sees. Can thoroughly recommend this book. I wish I had read this when I was in Moscow recently so that I could have visited the places mentioned in the book. If you enjoyed this you should also read Russian Roulette by Giles Milton. Another fantastic read about British spies in Moscow during the time of the revolution.