Here's four quite disparate pieces which all tell some aspects of the hidden history of twentieth century's "dark noon".
1. They say that to prove one has a mind, one must change it. Tawfiq Chahboune shows that to be true of one of the most sublime minds of the mid-twentieth century. In which incarnation was he correct? (Follow the interesting comments post.)
2. Helen Szamuely, one of the EU Referendum bloggers, has a fascinating article about Stalinist apparatchik turned victim of Stalinism, Willi Muenzenberg.
3. Snowball has an extremely interesting piece on the same period. The opening question is Was Churchill an 'anti-fascist freedom fighter' or an imperialist gangster? But the bit I found interesting starts half-way through with the material from Raymond Challinor.
4. On a lighter, if still grim, note, Snowball also gives some wonderful anti-Stalinist jokes collected in the Soviet Union in the 1930s.