The Three-Body Problem is a hard science fiction novel by the Chinese writer Liu Cixin. It is the first novel of the Remembrance of Earth's Past (Chinese: 地球往事) trilogy, but Chinese readers generally refer to the whole series by the title of this first novel. The second and third novels in the trilogy are titled The Dark Forest and Death's End. The title of the first novel refers to the three-body problem in orbital mechanics.
The work was serialized in Science Fiction World in 2006 and published as a book in 2008. It became one of the most popular science fiction novels in China. It received the Chinese Science Fiction Yinhe Award ("Galaxy Award") in 2006. A film adaptation of the same name was in production by 2015, but halted soon after.
The English translation by Ken Liu was published by Tor Books in 2014. It was the first Asian novel ever to win a Hugo Award for Best Novel, in 2015 and was nominated for the 2014 Nebula Award for Best Novel.