A book is a set of sheets of paper, parchment, or similar materials that are fastened together to hinge at one side. A single sheet within a book is a leaf, and each side of a leaf is a page. Writing or images can be printed or drawn on a book's pages. An electronic image that is formatted to resemble a book on a computer screen, smartphone or e-reader device is known as an electronic book or e-book. The term "books" may ...