Hollywood favors published books as source material for film projects because when a book is the foundation a lot of the heavy lifting is already done. As former Director of Media Services for Author Solutions Caroline Weiss explains, crafting an impactful story is the most challenging part of the film making process. If the story line is already developed it helps inform the screenwriters and filmmakers and puts them steps ahead in the process. A published book will also serve as another piece of merchandising/ marketing - book sales will help the movie ticket sales and vice versa. Any potential additional sources of income are very attractive to Hollywood.