The purpose of ISIL is to define and promote the use of a set of standard identifiers for the unique identification of libraries and related organizations with a minimum impact on already existing systems.
ISIL identifiers are assigned on request by the ISIL allocation agencies listed below. Libraries and other organisations may request ISILs also to their subordinate units such as branch libraries if and when necessary.
Both ISIL and ISNI (International Standard Name Identifier - ISO 27729) can be used to identify libraries, but they have different functions. ISNI is used in cataloguing for unique identification, whereas ISIL is used in circulation and interlibrary lending.
Non-national ISIL Allocation Agencies and code prefix for the identifiers
An ISIL country code is the equivalent of the codes specified in ISO 3166-1.
See ISO 3166-1 decoding table:
ISIL is developed within the framework of Technical Committee 46/Subcommittee 4 (TC46/SC4)
TC 46 - Information and Documentation - SC 4 - Technical Interoperability
SC4 at ISO homepage
International Organization for Standardization