Arthur Koestler is another one of those mythic intellectual figures of the 20th century comparable to Beauvoir, Sartre, and Malraux - random insertion: Weird that I automatically thought of French people here. Another one would have been Camus, a pied noir. Koestler's novel Darkness at Noon had originally been written in German (Sonnenfinsternis) but with the original lost the English version comes closest to the text of origin having been translated only once.
The author, formerly Communist himself, describes the fate of one Rubashov who faces trial in a schizophrenic totalitarian-socialist regime that he had helped built. Koestler here really mirrors the Moscow trials, Stalin's - successful - attempt to kill of and discredit the ones who had helped construct the Soviet Union in the first place. Rubashov and his contemporaries essentially are being forced to face the monster, the generation, that they themselves created. This generation does not doubt the infallibility of the party, of its No 1. While Rubashov in the course of his work came to doubt party decisions and its victims, well-meaning detractor of the party line, opponents to immoral attempts to assure economic success, his younger successors have learned to never shy away from that human cost.
Rubashov in the end, whether out of a need of self-sacrifice for a greater good or because of the physical pressure brought upon him, decides to toe the party line once more and implicates himself as a traitor and collaborator with foreign powers. A sad, but extremely humane story of a man in horror of what he helped create yet still unable to truly shake off its utopian appeal.