DOI System

The Digital Object Identifier (DOI®) System is for identifying content objects in the digital environment. DOI® names are assigned to any entity for use on digital networks. They are used to provide current information, including where they (or information about them) can be found on the Internet. Information about a digital object may change over time, including where to find it, but its DOI name will not change.

The system is managed by the International DOI Foundation, an open membership consortium including both commercial and non-commercial partners, and has recently been accepted for standardisation within ISO. Approximately 40 million DOI names have been assigned by DOI System Registration Agencies in the US, Australasia, and Europe.

To learn more about DOI names, see the Overviews, and begin with the Introductory Overview and Introductory Slide Presentation. The Factsheets, including the most recent on The ISBN System in Relation to the DOI System, and an updated DOI System and Internet Identifier Specifications discuss key topics about the system. For the most complete description of all aspects of DOI System technology and policy, consult the DOI® Handbook.

ISBN and ISBN-A
The ISBN (International Standard Book Number) is a 13-digit identification number and system, widely used in the international book trade for over 35 years and assigned through a network of international ISBN Registration Agencies. It applies unique ISBNs principally to physical books but also to related materials such as eBooks, software, mixed media etc.
The DOI® System offers a persistent actionable identifier for use on digital networks. A "DOI name" refers to the syntax string within the "DOI System". The ISBN-A ("the actionable ISBN") is a service powered by DOI®, in which an existing ISBN is expressed in the DOI System.

Syntax of ISBN-A
The ISBN-A is constructed by incorporating an ISBN into the allowed DOI syntax:
Example: 10.97812345/99990
The syntax specification, reading from left to right, is:

* Handle System DOI name prefix = "10."
* ISBN (GS1) Bookland prefix = "978." or "979."
* ISBN Publisher prefix = variable length numeric string of 2 to 8 digits
* Prefix/suffix divider = "/"
* ISBN Title enumerator and checkdigit = variable length numeric string of 8 to 2 digits

Note:

* the total length of the "Bookland prefix", the "ISBN publisher prefix" plus the "ISBN Title enumerator and checkdigit" will always equal 13 digits.
* the check digit from the ISBN remains unchanged; the DOI system does not use check digits.