And it provides a snapshot of the project that saves me hours of work when I’m preparing to evaluate a project. It gives me insight into marketing opportunities. A book proposal helps me learn more about an author than a two-sentence bio. When it comes to fiction, few agents or editors expect or require book proposals, but it’s an incredibly useful tool. It includes information on the content, the author, the market, and the salability of the project. A book proposal is a document most commonly associated with pitching a nonfiction book.