The Left Hand of Darkness
I know I've read other works by Le Guin (you can't be a sf fan and not, really), but right now I couldn't tell you what. I can, however, say that I'll search her out in the future, because I fully enjoyed this novel.
Look, I'm a Florida guy. I've never really seen snow that doesn't melt as quickly as it hits. The world she creates, Winter, with windows and doors built high on walls to accommodate for piled snow, doesn't reflect anything I've experienced in life. But Le Guin lays it out so well that I could feel the chill. I found it interesting, too, to be reading along, comfortably in that mindset of fantasy/sf based in a world simpler than ours and not as technologically advanced, and then have reference of telephone or something remind me that not all cultures progress along the same patterns. Something that many sf writers tend to forget, I think.
This is generally considered early feminist sf, although it deals more with the issue of gender itself than it reflects issues facing women in our society. Of course, in 1969 wanting to talk about gender in a probative way was pretty well left to the feminists, so there you go. So, do you fall in love with a gender or a person? Is good friendship, hard won and hard tested, the same as love? Can one type of love mutate into another? And, in a broader view, what does society look like when it's not split into her vs. him? When the question of sex drive is laid to rest and everybody gets laid when they need to and doesn't think about it when they don't? (Although, clearly, love itself - separate from sex - is a mystery regardless. That remains true.)
Of course, the other thing that remains true is that those in power wish to stay in power and will use whatever tools come to hand, including secret police and big fat lies. But then, what good is regional power against the idea of interplanetary merger?
final thought: I'm not normally one for a lot of gender theory, but Le Guin manages the story well enough to keep it interesting.