The Kalliope Union Catalog is a cooperative, offering libraries, archives, and museums an application to describe their archival holdings and making them accessible to the public online. By linking archival ressources to descriptions of persons, families, and corporated bodies in the Integreated Autority File of the German National Library, the Kalliope Union Catalog facilitates the retireval of archival information, both for its members and users. The combined union catalog includes, but is not limited to, personal papers, literary estates, manuscripts collections, and punlishers archives.