The labor movement or, more specifically, the trade union movement has always embraced the principle of internationalism. From the start, unions have not only strived to develop their national structures, but have also aimed at international cooperation. Accordingly, there has existed a socialist, a Christian, a communist, and a free international trade union federation. While the international trade union movement continues to pursue these aims, globalization gives rise to new challenges. Some of these challenges were examined and discussed at “The Past and Future of International Trade Unionism,” an international conference organized in Ghent, Belgium, on May 19–20, 2000. The event was organized by AMSAB-Institute of Social History, in collaboration with the Internationaal Instituut voor Sociale Geschiedenis (IISG, Amsterdam), the University of Ghent, and the International Association of Labour History Associations (IALHA).