An e-book reader, commonly known as an e-book reader or e-book computer, is a portable electronic device that can read e-books and other forms of e-books. There are many types of e-readers, including tablets based on Android and portable e-readers based on Apple. In addition, some readers also provided functions such as reading aloud, automatic classification, search, and bookmark. The price of e-book readers varied by brand, model, and function. Some readers also have additional functions such as audio output, video playback, and cameras.