Susanna Avery-Quash is senior research curator in the history of collecting at the National Gallery, London, where she is in charge of the research area of buying, collecting, and display. She has led research projects, organized conferences, and published extensively on the history of collecting and the art market. Christian Huemer is director of the Belvedere Research Center, Vienna. From 2008 to 2017 he headed the Project for the Study of Collecting and Provenance at the Getty Research Institute.