I read Brave New World by Aldous Huxley the other day. It was pretty good, better than most 'classics' I've read. I probably liked it better than Nineteen Eighty-four as well, which it's often compared to.

I found out later that Nick Bostrom explicitly used it as an example in some of his Existential Risk related writings, like this one, specifically, to illustrate what the 'singleton' or stable oppressive world government kind of existential risk may look like. If you aren't too worried that you might generalize from fictional evidence, I'd say it's worth a read if you somehow haven't already.