The book takes its title from a classical physics problem involving the effects – gravitational and climatic – of three celestial bodies occupying a limited space. It also refers to an immensely sophisticated “game” in which players enter a world (Trisolaris) dominated by three different suns. Under the shifting influence of these suns, Trisolaris cycles repeatedly between “Chaotic Eras” and “Stable Eras” as their planet moves inexorably toward destruction. When a signal from Earth—a compatible planet—reaches them, the Trisolarians initiate an extremely long-range plan to vacate their dying planet and make Earth their new home. The narrative ranges from the Cultural Revolution of 1967 to the imperiled present, illuminating events from the alternating perspectives of its human and non-human protagonists.