The book is that consists of the combination of the printed pages (made of paper, parchment, etc.) with a cover attached to the outside. It happens that a 'work' or part of a work is called a book. It is called bound objects, usually made of paper, where inscriptions in literature, philosophy, science and many other fields are presented as a whole. Books published electronically are called e-books, ie electronic books. In librarianship, it is also called a monograph to distinguish it from periodicals such as magazines, newsletters or newspapers. In the past, things like clay tablets and palm leaves were used instead of paper. Thus, the leaves of the book were also made from them. But none of these have been as durable as the paper we use today.