The Just City by Jo Walton
In this philosophical science fiction novel, the story revolves around the goddess Athena's ambitious experiment: to create a city based on the principles of Plato's Republic. With the help of time-travel and robots, she gathers scholars and thinkers from across history, as well as children to be educated as "philosopher kings," to populate the city. The narrative explores the complexities of implementing Plato's ideas in practice, examining issues of consent, the nature of excellence, and the pursuit of the greater good. As the experiment unfolds, the characters struggle with the challenges of realizing a theoretically just society and the ethical dilemmas that arise from their pursuit of an idealized vision of justice.