The answer is yes. Developmental editing takes care of the overall structure of your nonfiction book to make sure that it's optimized to deliver your message to your target audience. The aim of a developmental editor is to develop a deep understanding of your audience so that your book can be written from their perspective. First-time nonfiction authors tend to write books from their personal perspective. Experienced nonfiction authors write books from their audience's perspective. A developmental editor will help you make this transition.