ISBN (identifier)

An ISBN (International Standard Book Number) is a standardized identifier used to uniquely label a specific book product for discovery, cataloging, and sales. It does not identify the “work” in the abstract; it identifies a particular edition and format released by a specific publisher, which is why the same title can have different ISBNs for hardcover, paperback, e-book, audiobook, or new editions. Modern ISBNs are 13 digits (older ones are 10 digits) and include a built-in check digit that can confirm whether the number is structurally valid, but that math check does not prove the ISBN matches the book details you claim. For high-quality referencing, an ISBN should be treated as a product key that must be cross-checked against reliable catalogs or publisher records to confirm the exact title, author, publisher/imprint, edition, and publication date.