Adventure is a popular genre in movies because movies are a visual medium. Transformers and Avatar look great on the silver screen, but can they translate into a good adventure book. As a writer who has had to translate a story into a movie script, I know its' not easy.

A two-hour movie roughly translates to about 200 pages in a book, and most books are about 400-500 pages. Try talking Transformers: Revenge of the Fallen and try to make it into a book. It's going to either be filled with a lot more information than the movie or it's going to be very short.

That isn't to say that it hasn't been done. There are many books that were written around a television or movie idea. I mean, there are literally hundreds of Star Trek books that have been written since its debut in 1965. A few of them are based on specific episodes or movies, but the majority are new ideas simply set in the universe. That's easy.

In fact, you don't have to spend all that time introducing characters or back story because everyone is already familiar with them. If you're writing a Buffy the Vampire Slayer book, then you are assuming the reader already know who she is and what she does. They know Willow is a lesbian and Xander has commitment issues.

The fact is that books translate well into movies because it's much easier to take away than to add to, but movies don't make good books. Why spend 10 hours reading a book about something that you can watch on the screen?