Franz Kafka's unfinished novel Das Schloss (The Castle) was published posthumously in 1926 by his friend Max Brod, who ignored Kafka's instruction to burn his manuscripts. The novel depicts K., a land surveyor, attempting to gain access to a mysterious castle authority that seems to govern the village below while remaining perpetually inaccessible. The castle in Kafka's work is bureaucratic, labyrinthine, and omnipresent but unreachable — a perfect inversion of the medieval castle's visible, tangible authority.

Kafka's Castle became one of the most influential literary images of the twentieth century, transforming the castle from a physical fortification into a symbol of alienation, bureaucratic power, and the impossibility of reaching authority. The Kafkaesque castle haunted the poetry of Paul Celan, W. H. Auden, and many others who used fortification imagery to explore the opacity of modern power. The castle as a site of exclusion rather than inclusion became a dominant metaphor in twentieth-century European literature.