Updated by @unknown
Summary: Book and Quills item are missing from the creative inventory.
Original Description
I am a Minecraft player. I was playing Minecraft. However, after updating Minecraft, there is always a problem. Minecraft has no books and pens. So I am not good at Minecraft. Please fix this problem.
This is probably the result of changes that were made to item names used in commands. Somebody probably confused Book and Quill (writable_book) with Written Book (written_book), which is what a Book and Quill becomes after it's signed. The latter error is described in MCPE-100275.