This is one reason why I love Dan Simmons' books. (Hyperion, Fall of Hyperion, Endymion, Rise of Endymion, and even his more recent Ilium and Olympos.) They're all science fiction, and even on the very first page he introduces things without explaining exactly what they are, and leaves it to the rest of the text to put things in context for the reader to figure out.

That's not to say I always despise exposition, but I really don't like it when it's written in a condescending, let-me-hold-you-by-the-hand way, or when it interrupts the flow of the rest of the story.