This is one of those rare mind-blowing novels of such fantastic scope and direction that words just can't do it justice. It's the third book that started with the Hugo-Winning The Three-Body Problem, continued with The Dark Forest. They're all fantastic, but I have to honestly say that I loved this one more than the rest. 
 We've got the scope of some of Stephen Baxter's Xeelee Sequence* going on here. I'm talking universe-spanning scope, going straight through time like a hot knife through butter and right on out into the expanding reaches of the imagination. The first book dives into the tiniest particles and higher dimensional spaces, the second deals with the apparent macro universe and the ongoing conflict between the Tri-Solarans and Humanity, and the third concludes with some truly and amazingly harrowing experiences, from the end of the stalemate, the near-genocide of humanity, and the grand realization that it's all gone even more wrong. 
 And things only get worse from there. 
 I'm properly flabbergasted by this book. There are enough fantastic ideas crammed in here for ten books, maybe even twenty. And even if it wasn't so idea-rich, from the extrapolated sciences, extremely well-thought-out consequences, and even further extrapolations from there, we even get some of the more interesting characters ever written in SF. 
 My appreciation of The Dark Forest only increases when set beside this one, and although I didn't consider that novel quite worthy of the Hugo as the first novel was, it was an amazing set-up for this last novel's execution. 
 The Dark Forest is an expression of the idea that the universe is an extremely hostile place. Any two alien species that meets is likely going to preemptively wipe out the other or face the reality of being wiped out. Such conflicts at such huge scales and high-technology and physics can be utterly amazing and one-sided, from start explosions to local space conversions between dimensions, such as turning a local three-dimensional plane of existence into a two-dimensional one. 
 Utterly shocking. Utterly amazing. 
 We even get to visit, early on, the tombstones of entire alien civilizations that escaped the Dark Forest by hopping into the fourth dimensional frame from the third dimension, only to discover that the great time-stream is shrinking, a bunch of big fish already having consumed all the small fish, and now the pond of existence is shrinking to almost nothing. 
 Each new discovery or option or hope is explored and dashed. The conflict, the Sword of Damocles, never leaves the tale. The Dark Forest is always evident, and it's depressing and awe-inspiring and a great story and I was honestly in awe of all the new directions it took. 
 I've read a LOT of SF. I've never seen anyone pull this off quite as well as this. 
 He builds on every new idea and makes a universe as frightening as it is amazing, and nothing ever stays the same. 
 And best of all, he leaves humanity as it is. Hopelessly outmatched. Always hopelessly outmatched. No matter what we do, how we advance and improve or build upon inherited technologies from our one-time friends, dark gods, and demons, the Tri-Solarans, there's always a new snag. 
 *shiver* 
 Honestly, there's no way to review this except to tell everyone out there that there's just too many great things to say about it, that it is a monumental undertaking, that it is an endlessly fascinating and impressive corpus of work, and that everyone should avail themselves of this trilogy. 
 It's just that good. I'm in awe. 
 Some things are just heads and shoulders above the rest. Well, perhaps, this one is a whole storey above all the rest, too. :) 
 *Correction ;)