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 are androgynous and can change their gender at will. The story follows a human envoy named Genly Ai as he navigates the complex politics and cultural differences of Gethen. With its exploration of gender, sexuality, and societal norms, The Left Hand of Darkness has become a landmark work in science fiction.