Pretty Little Liars is one of the most literature allusion-laden shows on TV right now, and much like Lost before it, the references serve to enhance the show's central mystery plot line. There is no point in my trying to summarize what is going in in this show because its fifth season premiered last week and it is already so far down a ridiculous path that I wouldn't know where to begin, so I'll just say that it's the high school version of a "dead girl" show, and unlike its natural predecessors like Veronica Mars or Twin Peaks, it does not get bogged down by the central murder story in the slightest. It is extraordinarily campy, but also completely self-aware, and is just the best thing ever.

Many of the literary references provide actual clues and/or commentary (clever allusion to 'Dr. Jekyll and Mr. Hyde at the mid-season premiere of Season 4, for example), and some are hilarious red herrings. Just off the top of my head, there are deeply integrated references to The Bad Seed, The Great Gatsby, and Lolita. A quick skim of episode titles reveals no shortage of bad literary puns, so it's something of a treasure trove. For those interested, here is a Wiki of Book Allusions, but be warned! Spoilers abound.