Ursula le Guin is a wonder-ful and wonderful writer. If you are not familiar with her sci-fi-cum-fantasy work you are in for a real treat. Her most famous books are The Left Hand of Darkness, which is about a planet whose inhabitants are otherwise like humans except that they lack permanent sexual differentiation, and The Dispossessed, which asks questions about what is possible in the political and economic arrangements of our lives.
See how great she is? She's giving you two science-fiction books with weird technology, even higher mathematics and physics, and also a treatise on how our societies might look if we didn't have to spend so much time and agony over gender questions, plus a treatise on capitalism, anarchism and communism.
But she might just be most famous for her short story "The Ones Who Walk Away From Omelas." If you weren't assigned that in an ethics college course I recommend it for this Fourth of July long weekend*. In one sense it's a very short short story, in another sense you never get to its end.
My favorites among her books are still the EarthSea series. If you like Tolkien's The Lord of the Rings you might like Earth Sea. The latter describes a simpler world, the writing is more elegant and condensed, and its basic ethical frameworks different: Tolkien applied Catholic ethics to his world, le Guin applied Taoism.
But Earth Sea also has wizardry and dragons and all sorts of fun stuff.
The very latest books and story collections in the series are the best, with writing so honed that it's crystal-clear and sharp enough to cut, each word carefully picked to bear the largest possible meaning, everything superfluous abandoned, to allow the simple stories to be about truly large questions: death, freedom, love, our proper places in the plans of the universe.
I leave you with this quote from le Guin, useful when we try to understand why people often defend their own oppression:
“We will not know our own injustice if we cannot imagine justice. We will not be free if we do not imagine freedom. We cannot demand that anyone try to attain justice and freedom who has not had a chance to imagine them as attainable.”
* Wiser voices note that it might not be appropriate for a holiday weekend, being a bit depressing.