An ebook (short for electronic book), 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. Although sometimes defined as "an electronic version of a printed book", some e-books exist without a printed equivalent. E-books can be read on dedicated e-reader devices, but also on any computer device that features a controllable viewing screen, including desktop computers, laptops, tablets and smartphones

Some of the major book retailers and multiple third-party developers offer free (and in some third-party cases, premium paid) e-reader software applications (apps) for the Mac and PC computers as well as for Android, Blackberry, iPad, iPhone, Windows Phone and Palm OS devices to allow the reading of e-books and other documents independently of dedicated e-book devices. Examples are apps for the Amazon Kindle, Barnes & Noble Nook, iBooks, Kobo eReader and Sony Reader.