Ever been reading a book and get the feeling that the person telling the story isn't really telling you everything? Maybe the narrator is just a little too chatty, or obviously biased about something. Maybe they have something to hide. Something just doesn't feel right. Chances are you're in the hands of an unreliable narrator. An unreliable narrator is not godlike or omniscient, and in fact is not very trustworthy in the least.
Usually you'll meet an unreliable narrator in the form of a first-person narrator, like Edgar Allan Poe's notoriously unreliable ones. But unreliable narrators can come in third-person form, too—they're just a bit tougher to spot. Can you think of one?