An e-book (short for electronic book, also written eBook or ebook), also known as a digital book, is an e-text that forms the digital media equivalent of a conventional printed book, sometimes restricted with a digital rights management system. An E-book, as defined by the Oxford Dictionary of English, is "an electronic version of a printed book which can be read on a personal computer or hand-held device designed specifically for this purpose"^{E-books are usually read on dedicated hardware devices known as e-Readers or e-book devices. Some personal computers and cell phones can also be used, especially to read documents in pdf format.}