I suppose I don't read a ton of sci-fi, but this is one of the most satisfying payoffs I have ever read in any genre. This book drags a bit in places because Liu Cixin is incredibly meticulous about tying up loose ends and also feels the need to introduce a trillion new ideas, but it's all interesting and worthwhile. Once again, the dense science is balanced out with some very human, very heart-rending stuff. The whole trilogy is one of the best book series I've ever read. Can't say enough good things.