Orwellian and distopian fiction

Any other authors? There's a lot of bullshit sci-fi distopian fiction which focuses on cardboard characters and childish romantics.

But is there anyone else like Orwell or Huxley, or even Kafka - people with a theory, a focal point, a purpose? Philosophers, not just writers of rattling good stories?

I just finished A Handmaid's Tale by Atwood. Really excellent, thanks. I'll look at some of the others, but I can't imagine any modern writer topping Atwood's approach for me.