ISBNs are used to identify books and book-like products (i.e. audiobook or calendar) for each specific format and edition.  The purpose of ISBN identification for each format/edition of every title is that it enables efficient supply chain processing and marketing for book products by booksellers, wholesalers, distributors,  libraries, and universities.

For example, a title which is available as a paperback and hardcover would need two different ISBNs. Booksellers utilize the unique ISBNs to distinguish which title-format is being sold and so they can track and consequently reorder replacements. Ebook identification can be a bit more complex since many publishers assign unique ISBNs for each format (MOBI, EPUB,  PDF).

Common scenarios:

• Single ISBN – New self-publisher who is providing their first title in only a single format, such as a paperback.
• Five ISBNs – Publisher providing title in variety for formats to reach the largest audience. Five ISBNs would enable identification of paperback, hardcover, EPUB, MOBI and PDF formats.
• Ten ISBNs – Most Popular Selection –  Many of our clients purchase a block of 10 ISBNs to enable them to identify current and future books.  Due to the substantial cost savings, it is more economical ($280 for 10 ISBN & barcodes = $28 each).