A Square Object

I walked past the carpet toward the wooden shelf. There was a thick, flat object leaning upright against the wall. It was square. I stepped close and tapped the side with my foot. It fell forward flat onto the rug with a loud flop. It opened slightly like a mouth, showing thin white sheets inside. I sniffed one sheet. It smelled like dry paper and dust. I stood on the cover to test the weight. It did not move. I am rat. It is a book.