The third book in a truly excellent series. Jemisin does some amazing world building, with deep history and metaphysics that follow well, and believable characters. There's great depth here, and an awe-inspiring story.
I'll also add that I listened to the audio version, and Robin Miles as narrator is AMAZING. She uses different but consistent accents and tones for each character, making it easy to tell them apart, and greatly enhances listening to the story.
As a note (and I'll put this over in the warnings), there's a lot of child abuse in the first book. Like, a lot. Like, "I did not realize that was a trigger for me" a lot. The second book sees less, and it is mostly a mention in the third book, but it's very much present.