The Left Hand of Darkness. That’s her first scifi book I read and fell in love with it. I will add here the review I wrote when I read it:

In this book Genly Ai is sent to the planet Gethen on behalf of the Ekumen, an alliance of human societies residing on far flung planets, to acquaint the inhabitants with the existence of the Ekumen and convince them to join the alliance. The Gethenians are unique: every individual has the potential to be a man or a woman during regular periods of time, referred to as “kemmer”. The period of kemmer is the only time when a Gethenian has a defined sexuality. Throughout the course of the book any individual Gethenian is referred to as a “man”. The narrative is told through two POVs, both in the first person: Genly Ai, the Envoy; and Estraven, who is the prime minister of Karhide, Mr Ai’s liaison with the nation’s king. Over the course of the narrative, Le Guin explores a society totally uninfluenced by sexuality which interestingly holds up a mirror to how sexuality /gender permeates every nook and cranny of our social existence. It was however the beautiful depiction of the progression of the relationship between Mr Ai and Estraven that made me fall in love with this book. The complete disconnect between the cultures of the two main characters initially made them misjudge each other leading to dangerous consequences. Later, unexpectedly thrown in together while traveling for days in the icy wilderness, they begin to understand and accept each other for who they are; the story ultimately culminating into it’s heartbreaking conclusion. I will end with these beautiful lines: “Light is the left hand of darkness and darkness the right hand of light. Two are one, life and death, lying together like lovers in kemmer, like hands joined together, like the end and the way.”