Kit Whitfield’s In Great Waters is a truly unusual book. It’s hard to describe—it’s an alternate history where there are merpeople and that has changed everything. The merpeople—or “deepsman” to give them their proper name—are like a missing link between people and dolphins. They only need to surface to breathe every thirty minutes or so. They have tails. They are immensely strong. They have language but they are sub-sapient, they’re at a very interesting cusp of alien that we don’t see explored very much. They can cross-breed with humanity, and we first see them through the eyes of Henry, who is a cross-breed, or “bastard.” He has a bifurcated tail and can only stay underwater for fifteen minutes, but he can lie and say a shark is coming when he’s being bullied by the other children. It’s a lie that always works, and it works on the adults too. Henry has more cunning than the rest of his tribe but has less strength and power. Then he comes out of the water and begins to discover the world of landsmen and how he can relate to them. We discover it all with him, how similar and how different that world is from our history, what a difference the deepsmen have made.