The International Standard Book Number (ISBN) is a unique identification number which indicates one publication or edition of a publication, produced by a specific publisher, in one format. It applies to any single publication in printed, digital and mixed media formats, and each format of a publication is allocated its own ISBN.
The ISBN system is administered on an international, national and publisher level, and is standardised in the international standard, ISO 2108: Information and documentation. ISBNs assist with information processing in the publishing sector, distribution centres, bookshops and libraries.
Guidance on which products do and don’t qualify for an ISBN, and how to apply the number, is provided in the ISBN Users’ Manual https://www.isbn-international.org/content/isbn-users-manual.
Since 2007 the ISBN has contained 13 digits, which are divided into 5 segments, separated by a space or a hyphen for ease of reading.
In South Africa, should you wish to apply for an ISBN, contact the ISN (International Standard Numbering) Agency, which forms part of the National Library of South Africa.