Robota (2003) is an illustrated book by Doug Chiang and Orson Scott Card about a mysterious fourth planet of the solar system named Orpheus.

In a time before the events of the book, an alien race known as the Olm came to Orpheus and warned the people, explaining that their planet will crash into Earth in several thousand years.

The humans have reverted to a preindustrial existence in a world populated with chimerical beasts such as the saurian jodhpurs, relying on bio-sciences for whatever support they can derive.

With their mysterious leader, Font Prime, silenced, the robots have fallen under the baneful influence of Kaantur-Set, who directs a program of human extermination.

Eventually, Orpheus's fragments coalesced to form Earth's moon, which stabilized our planet's erratic rotation and allowed life to germinate.

The Mushroom City is, as the name implies, composed of massive fungal structures, carved hollow, and appropriated as great dwelling places.