Books to Movies: The Desolation of Smaug, Sometimes the Movie Can Explain Things

Jane Espenson supplies a great piece of commentary during an Angel episode: she notes a continuity error and then says something to the effect of "oh, well, the fans will explain it away."

The beginning of The Desolation of Smaug explains a great deal. For one, it establishes a more political subtext for the dwarfs' return to Erebor than occurs in the book (though political subtexts are implied in the book)--as well as the need for the Arkenstone. And quite frankly, the movie additions make more sense than Tolkien's "uh, we're going to get some treasure" quest. A burglar was never going to steal 14-people's worth of stuff! But a burglar could retrieve a jewel representing kingship.

Arguably, Tolkien didn't need to explain the quest in the book. As Tanith Lee points out in The Dragon Hoard, going to face down a dragon and recover treasure is as much a given as looking for a pirate hoard. The book is about Bilbo going on an adventure in which expected (and well-crafted) fairy tale tropes appear. 

Regarding those fairy tale tropes, I get the impression that Tolkien enjoyed writing Beorn and his house and his folktale persona more than just about every other part of The Hobbit. He spends a fair amount of time on Beorn, just as he spends a fair amount of time on the folk/mythical character Tom Bombadil in Fellowship.

Jackson skips Bombadil. He keeps Beorn, for good reason. Great character! In addition, in the movie, this character furthers Jackson's plot points. Beorn helps the dwarfs. He also gives Gandalf information that increases Gandalf's worries about Azog and the Necromancer, who is directly linked to Azog. Gandalf's necessary departure from the dwarfs and Bilbo is established. 

A book can spend more time exploring the world rather than moving through it. A movie needs to quickly establish WHY the moving-through-it needs to occur.  

What are the stakes?