The second novel in the Cixin Liu series about Earth’s Past series which began with The Third Body Problem.
This novel is great, and it’s a great follow up to the first novel. For one, it’s a branching off the good work of the first novel while also needing to be vastly different because of the ways in the which the narrative had shifted by the end of the first novel.
Knowing that an invading alien force is coming for the Earth, but not for several hundred years spins humanity off in multiple directions. From the “escapists,” who thinking leaving earth to the aliens and finding new worlds (or floating space ships) to inhabit is the best bet to “defeatists” who assume humans will lose the world and seek some kind answer with this certainty to the “wall-facers” who believe that we must defeat the invading forces, but have to protect against the telegraphic invasion of humanity of spies employed by the invading forces. The most of this novel takes place within the life of “wall-facers” a group of well-funded innovative thinkers looking for solutions in private. Fighting these are the “wall-breakers,” human spies who must fight against these plans.
The novel takes what’s great about the first novel and jumps into some amazingly inventive places.