A NISO/DCMI Webinar with Thomas Hickey, Chief Scientist with OCLC Research, will be held online at 1:00PM Eastern Time on 4 December 2013 (18:00 UTC - see World Clock: http://bit.ly/H3ccLC). Libraries around the world have a long tradition of maintaining authority files to assure the consistent presentation and indexing of names. As library authority files have become available online, the authority data has become accessibleand many have been published as Linked Open Data (LOD)but names in one library authority file typically had no link to corresponding records for persons and organizations in other library authority files. After a successful experiment in matching the Library of Congress/NACO authority file with the German National Library's authority file, an online system called the Virtual International Authority File (VIAF) was developed to facilitate sharing by ingesting, matching, and displaying the relations between records in multiple authority files. Although the most visible part of VIAF is an HTML interface, the API beneath it supports a linked data view of VIAF with URIs representing the identities themselves, not just URIs for the clusters. It supports names for persons, corporations, geographic entities, works, and expressions. With English, French, German, Spanish interfaces (and a Japanese in process), the system is used around the world, with over a million queries per day. This Webinar will cover some of the challenges VIAF meets in dealing with many different formats and approaches to describing identities, the relationship of VIAF to the source authority files, to other identity systems such as ORCID and ISNI, VIAF's approach to sustainability, governance and persistence, and how ambiguity is recognized and managed. Additional information can be found at http://www.niso.org/news/events/2013/dcmi/authority/. Registration for the webinar closes 4 December 2013 at 12:00PM Eastern (17:00 UTC).