Kafka's nightmar vision of a mind in distress

The utter strangeness of Franz Kafka's "The Castle" makes the novel compelling and in some ways off-putting. It's not easy to read, but it's also mesmerizing and hypnotic - you feel as if you're dreaming while you're reading it, with its dream-logic and nightmarish frustrations and obstacles. Though the overt sexuality is very tame by contemporary standards, I was surprised with how directly Kafka takes on sexual and Oedipal themes, which seem from my memory to play little or no overt role in his short fiction (maybe I'm wrong there). Toward the end of The Castle, Kafka has one of the character, Olga, soar off on a talking-jag monologue in which she explains to K. the history of her family trauma, which, in brief, occurred because younger sister Amalia (who is at times described as black) rejected an offer? command? from one of the messengers from the castle who wanted her as his mistress. This action was a huge insult to the authorities - one of the rules of behavior in the village seems to be that the women submit themselves to the will of the men in the castle, and it's actually an honor to be noticed and selected - which led to the ostracism of her family and their downfall. Of course it's never clear whether the man who sought her is really an authority figure, and there's constant debate and discussion about the messengers and servants at the castle, whether they really do anything, whether the people they work for are really authority figures - everyone seems to have heard of the power figures at the castle - Klamm, Sortini, et al. - but nobody's sure they've really ever seen them, nobody knows what they do, whom they work for - it's a nightmare vision of an authoritarian state and of a mind in distress.