The Left Hand of Darkness by Ursula K. Le Guin
Genly Ai is a human Envoy. He is the first visitor on Winter, a planet that is in the midst of a glacial age. They are advanced in many ways, unusual in others. To them Ai is a freak and not to be trusted. He is trying to introduce them to his interplanetary alliance.
Lord Estraven is the prime minister of the countries on Winter. He is Ai’s champion as well. While the other inhabitants of Winter look on Ai with suspicion, Estraven is working politically to get him accepted.
This is the beginning of an unusual friendship. Everything about Winter is unusual, from its climate to the beings who live on it. Ai does not understand Estraven or trust him. This is his story as he tries to get accepted and learn about these people. He does not realize how important Estraven will be in attaining his goal.
This is a fascinating story once the reader is into the second half. The first half is slow, confusing, and drags at times. The explanations and descriptions are needed to pull together the second half. That is when the story picks up and keeps the reader interested. It is worth slugging through the first half to get to the end. The inhabitants of Winter are different from other aliens we have met. They are fascinating to study.