The purpose of ISO 2108:2005 is to establish the specifications for the International Standard Book Number (ISBN) as a unique international identification system for each product form or edition of a monographic publication published or produced by a specific publisher. It specifies the construction of an ISBN, the rules for its assignment and use, the metadata to be associated with the ISBN allocation, and the administration of the ISBN system.

ISO 2108:2005 is applicable to monographic publications (or their individual sections or chapters where these are made separately available) and certain types of related products that are available to the public. Examples of applicable and non-applicable products are provided.