Query: Novels set in subterranea
Relevant documents:
The Tombs of Atuan
Deeper (Gordon and Williams novel)
Cavern of the Fear
Tunnels (novel)
Terminal (Tunnels novel)
The Master: An Adventure Story
The Secret People
Freefall (novel)
Closer (novel)
Spiral (Tunnels novel)
At the Mountains of Madness
Drome (novel)
Hidden World (novel)
Journey to the Center of the Earth
Level 7 (novel)
Plutonia (novel)
The Child of the Cavern
Etidorhpa
Mizora
Arqtiq