Necessity by Jo Walton
"Necessity" is the third book in a philosophical science fiction series that follows the residents of a distant planet created by the goddess Athena to experiment with Plato's ideal society. The story takes place generations after the founding of the city, where gods, humans, and sentient robots coexist. The narrative explores complex themes such as the nature of choice, the existence of gods, and the development of societies. When the planet faces a potential existential threat, its inhabitants must grapple with their destiny and the implications of their existence within a universe where the lines between myth and reality are blurred.