''The Castle'' is the story of K, the unwanted Land Surveyor who is never to be admitted to the Castle nor accepted in the village, and yet cannot go home. As he encounters dualities of certainty and doubt, hope and fear, and reason and nonsense, K's struggles in the absurd, labyrinthine world where he finds himself seem to reveal an inexplicable truth about the nature of existence. Kafka began ''The Castle'' in 1922 and it was never finished, yet this, the last of his three great novels, draws fascinating conclusions that make it feel strangely complete.