I try to remember here how I liked the books I read (and what books I read in the first place :-))
These books are only those that I really read to a big extent. So I leave out all the books I read half, but then had something better to do or technical books where I looked something up and then went on. And also I neglect Comics :-(
For the books I read in German, I will try to provide the english title.
While Urras is a world that refers to ours, Annares is a moon of it where anarchists have settled after the big revolution years ago.
Shevek, a brilliant scientist living on Anarres, visits Urras for the first time. He is overwhelmed by the beauty of the nature on that world, but shocked by the ways people behave there. The story hops back and forth often, we follow Shevek back to his childhood, to the present on Anarres that reveals the problems that this society faces after several years (the subtitle of that book is " An Ambiguous Utopia") and back to his visit to Urras again.
I appreciate LeGuin's intent to compare those worlds with each other by switching the context often, though it confused me a bit. Speaking of confusion, maybe I was a little too young, but there is lots of scientific theories that Shevek develops on his journey. I did not understand too much of that and it made me a little tired.
I just read that to many people in the Sixties, Anarres seemed like an Utopia compared to the America of that time. Today, more people feel that Anarres would not be a place for them to live. ItäS too long ago for me, but it shows one thing: What you think while reading this ambiguous approach, depends on how you feel in your life today. That might be a goal LeGuin achieved without actively going for it.
The book is a fascinating read and because I think I couldn't really appreciate it back then I always thought I should read it again (maybe I understand a bit of the scientific blah today :-)