The Philosopher Kings is the direct sequel to Jo Walton’s excellent novel The Just City. If you haven’t read that first book yet, stop reading this now and instead check out my review.

The new novel is set about twenty years after the end of The Just City. The Masters are growing old, the Children have grown up, and the Children’s children (somewhat clumsily referred to as “Young Ones” to avoid confusion) are the first generation of true philosopher kings, born into the Just City without preconceptions, as envisioned in Plato’s Republic.

In some ways, The Philosopher Kings is very similar to The Just City: a gently flowing story that combines philosophy with science fiction and fantasy, switching back and forth between several points of view. Returning from the first novel are the god Apollo, still disguised in human form, and Maia. The new p.o.v. character is Arete (“Excellence”, appropriately), the daughter of Apollo and Simmea, a teenager growing up in the Just City.

In other ways, this second novel is quite different: following the events at the end of The Just City, there are now multiple cities that follow separate interpretations of the guidelines laid out in Plato’s Republic. These cities occasionally raid each other for art work (one of the few truly finite resources), and it’s one such raid that sets off the plot for the new novel — a plot that involves much more travel and action than the first book.

It’s hard to say much more about The Philosopher Kings without resorting to spoilers, so I’ll just end this with a strong recommendation to check out these books. If you have an interest in philosophy they’re practically a must-read, but even if not, they’re simply wonderful examples of intelligent, thoughtful SF that tread some genuinely new ground and, despite their outlandish premise and setting, incisively ask questions about very real and current issues. Recommended.

(Finally, a small teaser for the fans: reliable sources tell me that the third book, Necessity, will have Crocus as a point of view character. Crocus! I. Can’t. WAIT!)

The Philosopher Kings is out today from Tor.