Cage of Souls by Adrian Tchaikovsky

Humanity clings to life on a dying Earth in an epic, far-future science fiction novel from an award-winning author.

The sun is bloated, diseased, dying perhaps. Beneath its baneful light, Shadrapar, last of all cities, harbors fewer than 100,000 human souls. Built on the ruins of countless civilizations, Shadrapar is a museum, a midden, an asylum, a prison on a world that is ever more alien to humanity.

Bearing witness to the desperate struggle for existence between life old and new is Stefan Advani: rebel, outlaw, prisoner, survivor. This is his testament, an account of the journey that took him into the blazing desolation of the western deserts; that transported him east down the river and imprisoned him in the verdant hell of the jungle's darkest heart; that led him deep into the labyrinths and caverns of the underworld.

He will meet with monsters, madman, mutants. The question is, which one of them will inherit this Earth?