Technically, After the Siege is a work of science fiction. But as with so many sci-fi stories, it works on two levels, exploring real-world issues like the plight of African countries that can't afford AIDS drugs. The upshot is that Doctorow's fiction got me thinking – on a Lockean level – about the nature of international law, justice, and property.Link
Which brings me to my point. If you want to read books that tackle profound philosophical questions, then the best – and perhaps only – place to turn these days is sci-fi. Science fiction is the last great literature of ideas.
From where I sit, traditional "literary fiction" has dropped the ball. I studied literature in college, and throughout my twenties I voraciously read contemporary fiction. Then, eight or nine years ago, I found myself getting – well – bored.