Half a century after the Doomsday Battle, the uneasy balance of Dark Forest Deterrence keeps the Trisolaran invaders at bay. Earth enjoys unprecedented prosperity. With human science advancing and the Trisolarans adopting Earth culture, it seems that the two civilizations can co-exist peacefully as equals. But peace has made humanity complacent ... The third instalment in the prize-winning space-opera trilogy after "The Three Body Problem" and "The Dark Forest".