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The ISNI database is not an authority file. Its sole goal is the creation of unique identifiers for public identities (the names by which persons and corporate bodies are publicly known) that are involved anywhere in the life cycle of intellectual and artistic content. (See ISNI FAQ) Therefore, many of the use cases that govern our library authority records (e.g., establishing consistent access points for use in bibliographic descriptions) do not apply.

Scope

The International Standard Name Identifier (ISNI) is a standard that uniquely identifies public identities involved throughout the chain of creation, production, management and distribution of intellectual or artistic contents. It identifies the public identities of parties such as authors, composers, cartographers, performers, academic and scientific authors, researchers, or publishers. (ISNI FAQ)

The database includes persons as well as fictional and legendary characters. 

Organizations (corporate bodies) are in scope for ISNI, but meeting names (conferences) are not.  Even though ISNI records may be found for some meeting names, new records for meetings should not be created pending discussions between ISNI and OCLC.

Is there a preferred form of name?

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ISNIs describe public identities, but pseudonyms are considered separate public identities. In this case, separate ISNIs are established for each just as is done in the LC/NACO Name Authority File  Each public identity relating to a given party shall have separate ISNI.
 (ISNI FAQ)  Records for multiple public identities of the same person are linked, but the links may be suppressed on request.