I am not a historian by training but the subject interested me: it is always difficult to venture to compare the Soviet and Nazi policies. I started with some distrust, but I was soon dazzled by the extraordinary quality of research, the accuracy of quotes and consistency of the narrative. The originality of the approach, which is to describe in detail the fate of several countries, caught between Germany and the USSR, over a period from 1930 to 1945, also the strength of the structure. The demonstration that these horrors were chained, famines caused the Holocaust by bullets and then to the extermination camps, becomes compelling.