Ebook files are electronic files that can be opened on digital devices known as eReaders. An eReader can be any device such as a computer, a tablet or a smartphone. The most popular ebook file format is the XML based ePub that can easily be read by several applications. Some popular eReaders include Amazon Kindle, Sony Reader, Hanlin and IRIX. An eBook can contain different types of contents such as text, image, and video.