An ebook , also known as an e-book or eBook, is a book publication made available in digital form, consisting of text, images, or both, readable on the flat-panel display of computers or other electronic devices

E-books are usually distributed on the Internet as downloadable files that can be read offline, as live Web pages that must be read online

The source of the catalog or metadata (which is data about the data) for a file may be entirely distinct from the source of the file itself

e-book files may exist in only one place, but anyone can access and download the files (whether for purchase or free download), because their metadata are freely available and can be freely shared