Agreed about A Fire Upon The Deep, optionally followed by A Deepness In The Sky. Those are classically styled hard science fiction novels with spaceships and a

Agreed about A Fire Upon The Deep, optionally followed by A Deepness In The Sky. Those are classically styled hard science fiction novels with spaceships and aliens. But much more thoughtful than you might expect from a typical spaceships and aliens scifi novel. If you're looking for something more germane to present concerns, Rainbows End is about a near future where people's interaction with the world is mediated by augmented reality and various forces are fighting over access to information. And since I haven't seen it mentioned here yet, Marooned In Realtime is also really good. But if you're looking for a single book, then you won't go wrong with A Fire Upon The Deep.