International Standard Book Number

ISBN – International Standard Book Number

The ISBN is a 10 or 13 digit unique identifying number assigned to books. The main purpose of the ISBN is to facilitate the supply chain. The ISBN is required for books to be sold in stores and placed in libraries.  The ISBN is not required if a book will not be sold in stores.

The ISBN is usually not required for eBooks but can be used if the author desires, additionally the ISBN can be used to distinguish a printed book from an eBook with the same title/author. If you are considering publishing your eBook on Amazon they use a unique ASIN number and do not require ISBN for eBooks, but you are free to purchase one.  You can purchase an ISBN and find out more information at isbn.org