Dear Mr. Rees,
While I tend to view you as one of the most serious historians covering this particular historical period I find your absence of any mention of Stalin’s' wiping out a generation of Marxists inside the former USSR somewhat strange.
In your book  Behind Closed Doors on page 94, you say that Stalin had no opposition inside the party. I think it would have helped your latest book if you had, at least, a chapter on the inner party struggle between Trotsky and Stalin.
I would like to know your views on Leon Trotsky or the Left Opposition which was opposed to Stalinism from the left. After all the Purges were a response to the growing influence of Trotsky and his ability to the counter the anti-revolutionary views of Stalin.
It would seem that this period of Soviet history is being erased or distorted in many new books on the subject, for example, the new biographies of Trotsky by Geoffrey Swain and Ian Thatcher
 World War Two: Behind Closed Doors: Stalin, the Nazis, and the West [Kindle Edition]