When I was in grade five, my class went to the library and we learned about how to treat a book.

When you get a new book and you want it to lie flat and stay in good condition, we were told, you need to follow a certain process. Start with the book closed and vertical with the opening facing you and the spine on the table.

We were shown to open each cover and then successive outside pages folding them outward “training them” to lie flat. After several individual pages, the librarian showed us to take several pages at once and fold them outward along the spine.
The background image for the pedia shows the result of not following such directions, a cracked spine.