Good modern allegory, definitely in the lineage of Lindsay's Voyage to Arcturus, MacDonald's Phantastes, as well as images of the Scottish country life that would be at home in John Galt or Lewis Grassic Gibbon. It also looks forward to C.S. Lewis's Space Trilogy, especially That Hideous Strength, and even to works like Ishiguro's The Buried Giant and the TV show Severance.