The Left Hand of Darkness is a science fiction novel written by Ursula K. Le Guin. It is set on the planet Gethen, where the inhabitants have no fixed gender and can change their sex at will. The story follows a human envoy as he navigates the complex social and political landscape of Gethen. The Left Hand of Darkness explores themes of gender, sexuality, and cultural differences. It is considered a groundbreaking work in the science fiction genre and has won numerous awards.