The e-book is a digitized version of a book, meant to be read on a computer, e-reader, tablet, or smartphone. In addition to major titles, self-published books play an important role in the e-book market. The goal of the e-book is to provide the ability to read books through an onscreen interface rather than on paper. In the communication ecosystem perspective, the text and images of the e-book are the content. Though key to the original e-book market, e-readers are not necessary to read an e-book and many e-book users read on computer, tablet, and smartphone screens. The spread of e-books would be limited until a large-scale diffusion of personal computers, the Internet, and online retailing created the right environment. The success of the iPad and other tablets in the e-book market has helped establish what will likely be the most important hardware for the future of e-books.