Interesting...

I've mentioned before how adaptations fascinate me. I just read this blog entry today that offered some insight into the book-to-screen adaptation of Up In The Air. I haven't had the chance to see the movie yet, but the blog entry implies that the screenwriters explored the world the novel set up, rather than transcribe the story beat for beat. That kind of adaptation is more interesting to me, because if I wanted to know the exact plot of the book... I'd just read it. Instead, I'd rather observe how the story can transform through the collaborative process of film making. Judging from the early Oscar buzz I've been hearing for the movie the past few months, it sounds like it paid off in this case.

Does anyone know how much of a part author Walter Kirn, who wrote the novel the film is based on, had in the adaptation?