Death's End, by Liu Cixin
The third book of Liu's trilogy, and for me the least successful entry. Much of the book is like an expanded gloss on some worldbuilding exercise in imagining the different 'ages' of human history that might occur.
As I've mentioned before, Liu seems much more influenced by Golden Age SF than anything current. Nothing particularly wrong with that, except that some tropes do not age well. Nebbish boy attracting unattainable girl by extravagant gesture.
Also marred by some inexplicable psychology. When Mutually Assured Destruction is the order of the day, the response to one side destroying the other is not 'you win, we'll leave you alone'.
As I've mentioned before, Liu seems much more influenced by Golden Age SF than anything current. Nothing particularly wrong with that, except that some tropes do not age well. Nebbish boy attracting unattainable girl by extravagant gesture.
Also marred by some inexplicable psychology. When Mutually Assured Destruction is the order of the day, the response to one side destroying the other is not 'you win, we'll leave you alone'.