The Night Land by William Hope Hodgson
Aeons in the future, Earth's surface faces perpetual night after the failing of the Sun. Humanity is entrenched within the Last Redoubt, a colossal metal pyramid. Beyond the safety of its structure lurk countless unknowable threats. William Hope Hodgson's strange, visionary novel of humanity's struggle for survival in the eternal darkness of the future was first published in 1912, and is widely acknowledged to be one of the foundation works of the 'Dying Earth' subgenre of Fantasy and Science Fiction. Written in a style composed of strange archaisms which fuel the weird sense of disorientation, this cult classic has won the admiration of writers from Brian Aldiss to C S Lewis, who wrote: 'The Night Land gives, like certain rare dreams, sensations we never had before.'