The Three-Body Problem is a science fiction novel written by Liu Cixin. It is the first book in the Remembrance of Earth's Past trilogy. The story takes place in both the present day and during China's Cultural Revolution, as humanity becomes aware of an impending alien invasion from the Trisolaran civilization. The book explores themes of physics, philosophy, and the nature of humanity's place in the universe. With its intricate plot and mind-bending concepts, The Three-Body Problem has gained international acclaim and is a must-read for fans of alien mysteries and science fiction.