Provenance research is an international discipline, just as the art and cultural property it traces are international in origin and influence. At AAM's 2004 International Provenance Research Colloquium, specialists from North America met with colleagues from western and central Europe to exchange information on the general topic of provenance research, with an emphasis on World War II provenance issues. Topics include the collections of the Nazi elite, recreation of historic family collections, case studies of specific object provenance, accessing lesser-known archival resources, and the structure of the art trade in the twentieth century. These proceedings highlight significant strides in provenance research resources and methodology, and also illuminate the number of different sources, many of them little known to North American researchers, that may have to be consulted to clarify the provenance of any one object.