A book is a collection of sheets of paper, parchment or other material with a piece of text written 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.

Publishers may produce low-cost, pre-proof editions known as galleys or 'bound proofs' for promotional purposes, such as generating reviews in advance of publication. Galleys are usually made as cheaply as possible, since they are not intended for sale.