The "three-body problem" is a classic physics problem that suggests if you have three celestial bodies in motion, determining their position with respect to each other at an arbitrary time is essentially impossible - at least with our current science. We can model it, we can approximate what will happen, but we cannot give a definitive answer. (Wikipedia article.)
The Three-Body Problem is also Cixin Liu's Hugo winning science fiction novel, and one of the most lauded SF books of the last decade. The premise is "What if we're speaking to the stars, and someone really is listening? And that someone isn't friendly?"
The book opens during the Cultural Revolution with the intent of establishing the motives of one of the characters, although it also acts as a refresher for those of us who aren't Chinese and/or didn't live through that horror show. To me the stuff about the Cultural Revolution felt more like Cixin Liu expressing his disgust with that portion of Chinese history than a significant plot point. But he's a science fiction author, and a lover of science (not all SF authors are, but he's clearly into the hard science) - he knows that he'd have been an "enemy of the revolution" and killed or sent to a farm to die doing hard labour. Undoubtedly Liu didn't intend this section to be about himself, but that's all I could think about while reading it.
And here we come to the problem of translation. I found the afterword by translator Ken Liu fascinating: he was obviously thinking about many of the things I was thinking about as I read the book. One of the more obvious problems is "how do you make the book comprehensible to a North American audience without filtering out the Chinese culture that permeates the entire book?" I found my biggest problem with translated prose very present here: the text seems wooden and awkward, despite Ken Liu's best efforts. And since I don't speak the language, I'll never know if that woodenness is the fault of the original author or the translator.
2019-12 UPDATE: Liu Cixin 'recommends that Chinese sci-fi fans who speak English read Ken Liu’s translation of The Three-Body Problem rather than the Chinese version. "Usually when Chinese literature gets translated to a foreign language, it tends to lose something," he says. "I don’t think that happened with The Three-Body Problem. I think it gained something."' ( https://www.nytimes.com/2019/12/03/magazine/ken-liu-three-body-problem-chinese-science-fiction.html ) Wow.
But it seems likely that the broad and often unconvincing characters can be laid at the feet of Cixin Liu. He lays out logical reasons to tell us why they are who they are, but he still doesn't manage to sell it - at least not to me.
Another problem with the book is the "Three Body" video game. As described in the book, nobody would play it. It looks unattractive, you freeze or cook in your v-suit, there's all kinds of death and no action, all you get is infrequent thought problems presented in a particularly hazy way.
I found the book mildly interesting, but I don't think I'm going to follow through to the two sequels as the writing really doesn't work for me.
I wanted to add some comments and quotes I found relevant, but these can be considered spoilers so if you're going to read the book, stop reading now.
Another major issue I have with the book is the title: it's taken from the classic physics problem, but really it's a four body problem. Three suns AND a planet. The planet is probably gravitationally insignificant, but it's a fourth body and arguably all-important because that's where the people live.
Here's a rant from an alien: "Existence is the premise for everything else. But ... please examine our lives: Everything is devoted to survival. To permit the survival of the civilization as a whole, there is almost no respect for the individual. Someone who can no longer work is put to death. Trisolaran society exists under a state of extreme authoritarianism. ... Anything that can lead to spiritual weakness is declared evil. We have no literature, no art, no pursuit of beauty and enjoyment. We cannot even speak of love ... is there meaning to such a life?" I was struck by how blatantly UNalien this rant was - despite his having set up a radically different biology than our own. We don't understand the people on the other side of the planet and he thinks people in another solar system will be this human?
And then there's the author's afterword, which includes this quote:
There's a strange contradiction revealed by the naïveté and kindness demonstrated by humanity when faced with the universe: On Earth, humankind can step onto another continent, and without a thought, destroy the kindred civilizations found there through warfare and disease. But when they gaze up at the stars, they turn sentimental and believe that if extraterrestrial intelligences exist, they must be civilizations bound by universal, noble, moral constraints, as if cherishing and loving different forms of life are parts of a self-evident universal code of conduct. I think it should be precisely the opposite: Let's turn the kindness we show toward the stars to members of the human race on Earth and build up the trust and understanding between the different peoples and civilizations that make up humanity. But for the universe outside the solar system, we should be ever vigilant, and be ready to attribute the worst of intentions to any Others that might exist in space. For a fragile civilization like ours, this is without a doubt the most responsible path.
Woo - now that's xenophobia. And, despite that, I kind of agree with him. On the other hand, he's entirely ignoring the SF of the 1930s through the 1960s, in which we went to the stars and absolutely kicked butt: we conquered the same way we took over other continents on our own planet. But now SF - along with almost every society on the planet - is claiming that conquering other cultures is bad. That's the politically correct thing to say these days.