The question of how to deal with cultural property or looted property held "in trust" concerns libraries, archives, museums, and Jewish institutions. While ordinary kinds of acquisition in cultural institutions, i.e. purchases, donations, deposit copies or exchanges, have been examined within the scope of NS provenance research, another type of transaction has been mostly overlooked so far. It concerns the transfer of objects with conditions attached, with institutions accepting items "in trust", as loans or as legacies, or objects being allocated to institutions by the state, which occurred as part of NS book and art looting as well as in the course of later political developments. On the basis of how libraries, archives and museums have so far dealt with cultural objects held "in trust", national and international librarians, historians, curators and legal experts are invited to discuss structured procedures and lead an interdisciplinary debate on the requirements, chances and limits of appropriate measures concerning objects which have been illegally acquired and have been received "in trust".