One of my books has gone missing from my bookshelf (and maybe it's not the only one).
I know I entered it before - the Library says it's on my bookshelf, and it's front and center on my physical bookshelf, so how could I have missed it?
Even tho the Library says it's on my bookshelf, I have searched from within my bookshelf by keyword, author's name, and ISBN. The book never comes up.