I'm confused about where Luffy and Nami are trapped. Are they trapped in a book or in a cell. And what is the world of books?
Its a Devil Fruit power possessed by one of Mama's children. So the world of books is just one of its techniques...
Its not actually another dimension compared to the world of mirrors. World of books were more like a super dimensional/visual illusion
It's the power of Charlotte Mont D'or.
What do you think?