It is a software application that is capable of reading ePub files, the standard for digital books, from your Android device. What is ePub? The ePub format was developed in accordance with the standard by the International Digital Publishing Forum (IDPF) as an open standard for digital books. IDPF is an international nonprofit organization that aims to provide a standard for digital books. IDPF is the main organizer of the ePub standard, which is an open-source format that allows authors to publish their books in a simple way, without having to pay anything. The ePub format was created to be a low-cost, low-power consumption format, to be able to be used on all kinds of mobile devices. It was designed to work on mobile devices and the ePub format is optimized for mobile devices. It allows authors to add their books to online catalogs and store them in online libraries.