Prequels get a bad wrap... and deservedly so: they're notoriously hard to pull off, and rarely feel worth the effort that it takes to create them.
The problem is that they usually set out to fill in gaps that were left ambiguous on purpose the first time round. You know, things that were done to create a sense of mystery or make the main hero into something of an enigma. Who cares how Han Solo became Han Solo, anyway? Isn't it better to leave what happened "before" to the imagination? According to Hollywood, the answer to that question is: "Uh, no!"
Despite the fact that most prequels are terrible, however, there are a handful that are genuinely worthwhile; movies that - believe it or not - justify their existence in clever, interesting ways and don't squander what was good about the originals.
Here are 10 prequels which prove that this sequel sub-genre isn't quite as redundant as many movie-goers seem to think; that it's actually possible for a prequel to both enhance its predecessor and the established mythology...
Note: Some films often labelled as "prequels," like Batman Begins and Casino Royale, haven't been included on account of their being part of their own, separate universe; I've opted for prequels made as part of an existing canon.