There is a strong urge to create books that are unconventional in style and form, where experimentation with language and design must be an essential addition to the story.
See a book page as a blank canvas of paint on which anything can arise, rather than a page that must be written full. So you can combine prose (fiction) with essays (non-fiction).
Or use poetry with dialogues from theater texts, photos or drawings to tell a story. Continually exploring the boundaries of prose, poetry and experimentation, but always keeping an eye on plot and story.
The hybrid novel, where form is content and content is form.