A book is a collection of sheets of paper, parchment or other material with a piece of text writen on them, bound together along one edge within covers. A book is also a literary work or a main division of such a work. A book produced in electronic format is known as an e-book.
In library and information science, a book is called a monograph to distinguish it from serial publications such as magazines, journals or newspapers.
Further information and links:The Book
History of the Printed Book