Non-fiction books are just that: not a work of fiction. This means, of course, that the book is true or about real things. There are hundreds of topics, which include categories, such as history, science, religion, childbirth, child development, behavior, archeology, geology, and so many, many more.
Entrepreneurs write non-fiction books about what they do, which can be a carpenter, marketer, financial analyst, and so many others. There is no difference between what an entrepreneur writes about his or her business topic than someone else who writes a non-fiction book. The purpose for the book might serve in a different manner.
The structure of a non-fiction book does not follow any standard formula. However, adding some storytelling features into non-fiction can punch up an otherwise dull text. For example, adding anecdotes when possible and relevant helps the reader relate better.
Non-fiction books may require illustrations, depending on the topic. For example, a non-fiction book on childbirth or dance could both be enhanced with pictures.