An eBook is an electronic or digital version of a printed book. eBooks can be read on computers, eReading devices or on your smartphone.

What file formats are eBooks available in?
eBooks come in a variety of formats, though most commonly they are found as PDFs or as ePubs. An ePub (electronic publication) is an eBook standard that allows for flexibility when displaying text on different devices or hardware, and has been embraced by many publishing and technology companies, including Sony, Apple, Google, Random House, Harper Collins and Adobe.

ePUB Devices
You can read ePub formatted books on your computer, on many mobile devices, such as iPhone and BlackBerry, and on select eReaders such as the Kobo eReader