We recently posted an article reviewing historian Norman Naimark's book, "Stalin's Genocides", which concludes that there was more similarity between Hitler and Stalin than usually acknowledged: "Both chewed up the lives of human beings in the name of a transformative vision of Utopia. Both destroyed their countries and societies, as well as vast numbers of people inside and outside their own states. Both, in the end, were genocidaires."
Tymothy Snyder's latest book, "Bloodlands: Europe Between Hitler and Stalin", appears to follow on from this theme. In Saturday's edition of "The Guardian, newspaper, Neal Ascherson reviews the book and concludes that Auschwitz and Siberia are only half the story...
See also: http://www.ft.com/cms/s/2/b4ac852e-e2e0-11df-9735-00144feabdc0.html