The ice does not care what I decided he was
Genly Ai is an envoy on a planet where people are not men or women except for a few days a month, and he spends most of the book failing to see the one person who is actually on his side. Estraven talks to him as an equal. Genly keeps translating that into the categories he brought from home, and the translation makes Estraven look dishonest. I have read enough science fiction to expect the planet to be the point. The planet is the condition. The point is two people pulling a sledge across the ice when one of them has finally run out of wrong names.
The journey is cold in a literal way. Food, crevasses, the tent, the days when they do not speak. Le Guin does not hurry it. By the time Genly can say what Estraven is to him, the word he reaches for is not a theory about gender. It is the name of a person he will not get to keep. I had known the famous line for years, the one about light and dark each being the left hand of the other. Inside the book it is not a slogan. It is something Estraven copies down because the old religion of his country already knew it, and Genly is late.
I read the ice chapters in one sitting and then went back to the early pages, annoyed at Genly and a little annoyed at myself for sharing his mistake. That is a good annoyance. It means the book did not let me stay the visitor.