The Killing Moon is the first story in Jemisin's pair of Dreamblood novels. It has a Nebula nomination in 2012, and I will not be at all surprised if the second entry doesn't get an award nomination too. It's a fun story that works on many levels, I had fun thinking about it.
I would say at first that I thought the story was a bit simple--it is told in a much more subdued way than the kind of bombastic Really Big Magic style of her Inheritance trilogy. It still goes pretty big at the end, but builds to it slowly. The Killing Moon is mostly human-scale. The main character is Nijiri, an apprentice Gatherer. Gatherers collect the "dreamblood" from those they cause to die, and perform other healing magics with it or give it to others in their path to use. It's a powerful magic, though, that is easy to misuse. So a central theme is how the Gatherers discipline themselves to handle this awful, volatile power.
A couple of metaphors stand out for me. One is that this is a vampire novel. Now, it's a good vampire novel because it is subtle. The mythos is roughly Egyptian, but all the other vampire tropes are there--the beauty of the practitioners (commented on many times), the struggle for control of powerful magic, the "dreamblood" taken--maybe it's not even all that subtle. Jemisin admits to no vampire influences in the acknowledgements or accompanying material, but it's pretty clearly there.
But it goes bigger than the vampire novel in that the power is potentially world-scale in a single individual. Control of it can slip without the practitioner noticing. Gujaareh has used this power to become great. There's something of a nuclear power metaphor here--the other nation involved, Kisua, has sworn off narcomancy (the power is all in dreaming) because of the dangers. Things can and do get out of hand, and it's sort of surprising it didn't happen sooner.
Anyway, very good stuff, it very much grows on you as it goes. Four stars from me.