A collection of paper, parchment, or any other material containing print, paintings, or other inscribed works that are all bound between two protective covers are called Books. However, an e-book is is a collection of text that is electronically formatted. Antique books come in the form of scrolls and codex. The protective binders that contain the sheets of paper containing writing may come in a hard protective cover called a hardback or in a softer, flexible cover called a paperback. Novels are the most popular form of books, although works such as The Holy Bible and The Koran are referred to as "The Book."