I haven't read her myself yet, but Ursula K Le Guin is of note. Lathe of Heaven, The Ones Who Walk Away from Omelas and The Word for World is Forest are worth looking at.
Terry Pratchetts work is very good. Lots of humour and light parody of fantasy tropes, and some occasional commentary. You could probably pick almost anything from the Discworld series and find something enjoyable.
October By China Mieville is an account of the Russian revolution of 1917. It's not written as a perhaps more dry, academic account, but still decently researched and a good introduction that's easy to read almost as if it was fiction. Apparently his science-fiction is good too, but I have no idea.