Welcome to the U.S. ISBN Agency! Bowker is the official source for ISBNs in the United States. An ISBN uniquely identifies your book, and facilitates the sale of your book to bookstores (physical and digital) and libraries. Using ISBNs allows you to better manage your book's metadata, and ensure maximum discoverability of your book.

ISBN stands for International Standard Book Number and is a 13-digit number that uniquely identifies books and writing-related products. How many ISBNs do I need? A single ISBN will cover 1 format of 1 book. So if you’re publishing 1 book in paperback and ebook format, you’ll need 2 ISBN numbers. ... Once you purchase an ISBN, it will stay ...

An ISBN is an International Standard Book Number. ISBNs were 10 digits in length up to the end of December 2006, but since 1 January 2007 they now always consist of 13 digits. ISBNs are calculated using a specific mathematical formula and include a …

An ISBN number is the "International Standard Book Number" which is a unique ten or thirteen digit number that is assigned to every printed book. A book's ISBN number identifies the title and the publisher of the book it is assigned to. Our unique multiple ISBN search allows you to enter one or more ISBN numbers to be searched for ...