Why do some of my books have a cloud arrow icon?

bookshelf-download-large@3x.png

If your Bookshelf has to retrieve a large file (such as a long video, or an image-heavy PDF) from the Know Me server, it will put a “downloading” icon on the cover of the book while it loads in the background. While the file is downloading, you won’t be able to tap on it to view it. Once the file is ready, the icon will go away and you can view the item as usual.