Veteran novelist Catherine Ryan Hyde, author of Pay It Forward and 15 other books wrote two great articles on the book publishing business on DailyFinance.
In the first, The (Paltry) Economics of Being a Novelist, she describes the monetary underpinnings of the novelist's business. She talks about things like advances, royalty checks (apparently authors get only two a year), the shelf life of a novel, and other such things. The inevitable conclusion is, of course, don't do it for the money.
In the second, The (Unlikely) Economics of Your Book Becoming a Movie, she described how novelists (theoretically) profit from their books. She tells about her experience from when Pay It Forward was adapted to film. No surprises here either: if your name isn't J.K. Rowling or Stephen King, there's mostly no money and definitely no creative control.
Great articles for anyone ever entertaining the thought of being a novelist and wondering about the process, the business side of things, the journey, etc.