It is my great pleasure to welcome you to “Repositories in Cooperation”. Our panel for “Varieties of Cooperation” developed out of preparatory work for the Collaborative Research Center „Media of Cooperation“, in which we have attempted to refocus and reappropriate Susan Leigh Star’s and James Griesemer’s original notion of the boundary object. Within our 2015 workshop on “The Translation of Boundary Objects” we have started to re-engage with a more specific understanding that returns to Star’s list of four type of boundary objects: repositories, ideal types, coincident boundaries and forms/labels. The results of this have now been published in German as “Grenzobjekte und Medienforschung”, along with a translation of ten seminal texts by Star and her collaborators. As Erhard Schüttpelz has shown in his commentary on “This is Not a Boundary Object” all four types deal with the relation between modularity and extendability, with the relation between “parts” and “wholes”.