Wholly original, absolutely genius, and utterly devastating. It's a slow-moving volcano of magical geology, family, apocalypse and hope. It starts with so many questions- the narrator speaks with colloquial jokes, directly addressing the reader out of time, but the characters are completely immersed in their incredibly built world. You won't love any of these people, but you will follow their stories, and marvel at the things they do, and the places they go. There is nothing quite like it in the genre.
I'm in. I need the next one. But I would give this warning to would-be readers: Jemisin's work is as soul-crushing as it is wondrous. It's dark, graphic, and adult in every way. Still, it's one of my favorite fantasy works to date.