When talking about adapting a book, the term usually concerns whether a book can be adapted to the screen. The concept is broader. Essentially, all writing is adapting.
At times, this involves rearranging the concepts, or adapting them, to best translate them to the medium of a book. I have worked with clients who were gifted speakers and lecturers. When we developed their books we found that the way they structured their presentations, key note speeches and lectures would not translate directly on the page. The medium of the book gave a different scope and dimension. It gave room to explore ideas further or in a different way. This meant the idea had to be adapted and restructured in order to be communicated clearly and effectively.
Structuring the book to its strengths is essential to conveying the ideas and concepts that inspired the book in the first place. Business coaching guides, academic texts, genre fiction and screenplays all have different requirements of structure. What remains consistent is the need for rhythm and growth. In a story this involves increasing tension. In non-fiction manuscripts this is the hook that adds up through the chapters to communicate the concepts. In both cases, proper structure grips the reader and builds the momentum.
Finding the best way to structure your story is the first step to adapting your concepts and ideas to a book.