I confess, I've never really read Le Guin apart from a not particularly enthusiastic attempt at The Left Hand of Darkness. The science fiction I largely read when I was younger was from the 1950s greats and the 1960s new wave, and while I read their later work too, and have started picking up on some newer writers, there's a big gap in my experience, including pretty well everything Le Guin wrote.
The book does have some science going on - the main character is a physicist developing a theory on time (hence the ansible cropping up), which seems mainly to be based on the block universe - but it's not really what the novel is about. It's far more an exploration of political systems. Our hero, Shevek, lives on the desolate Anarres, where humans can live, but are always fighting for survival. But he begins to find out more about and even to correspond with the twin planet Urras, which is lush and beautiful, eventually breaking with tradition and visiting it.
The drama comes from the juxtaposition of very different political systems. The main country on Urras is decadent capitalist, though the planet also has a Soviet-style communist country. Anarres is anarchist communist - not only is there genuinely no personal property, there are no laws, no rules.
Cleverly, in making the contrast between Anarres and Urras, Le Guin brings out the faults in both systems. It might seem at first that, despite the hardships, the anarchist Anarres is a paradise, because Le Guin manages to come up with a structure that would allow anarchy to work practically as a regime - no mean feat - but in reality humanity likes rules, and they are actually there, concealed and unspoken, until Shevek begins to break them.
It's absolutely not my kind of science fiction, and yet I found it both fascinating and enjoyable. I just wish I also now knew more about ansibles.
You can get The Dispossessed from Amazon.co.uk and Amazon.com (why no Kindle version, btw - it should have one to bring it to a new audience.)