You may have noticed a set of numbers (usually 10 or 13) that are separated with dashes and are located toward the bottom of the ‘copyright’ page and wondered, what exactly is an ISBN number? It stands for The International Standard Book Number, or ISBN (sometimes pronounced “is-ben”), is a unique identifier for books, intended to be used commercially.  The ISBN system was created in the United Kingdom in 1966 by the booksellers and stationers W H Smith and originally called Standard Book Numbering or SBN. It was adopted as international standard in 1970.

You can obtain an ISBN number through Bowker and there is a service fee to process all ISBN applications and it typically takes 15 business days. For more detailed information visit the 
U.S. ISBN Agency, the official source for ISBNs in the United States.