Recent upgrades to the Pressbooks software allow authors to incorporate a variety of interactive elements in their books.  With H5P authors can create rich and interactive web learning experiences such as quizzes, fill-in-the blank, matching and image-based activities.  Hypothesis,  annotation and note-taking software, can be added to the published version of your book to allow your readers to hold discussions, read socially, organize their research and take personal notes.  Glossaries can be created to provide definitions and supplementary material that can be activated by readers of your book