Book
A Book lets you place large amounts of text and images into a course, in a way that does not disrupt the course layout.
After creating a book (which has fields that are common to all elements) and opening it, you will see an experience like this:
On the Overview tab, is the same summary visible on the course page. If you click Add a new page, you can add pages to your book.
These pages will then be displayed in the navigation area, and can be re-organized.