The symposium, “What Was Sustainability?: The Past, Present, and Future of Sustainability in Design and its Education,” March 26-27, 2025 at the Delft University of Technology, will bring together educators and researchers to explore the history of sustainability, as a concept and set of practices, in design and design education. The symposium will focus in part on the story of industrial design at TU Delft, with the goal of contextualizing that within larger narratives of Dutch, European, and global design education, as well as of sustainability beyond design. A collaboration with IIT Delhi and a counterpart to the SiDE Symposium there in January (link), we are interested in transnational, comparative, and postcolonial/decolonial perspectives. Though the center of gravity will be industrial design, we welcome perspectives on related design fields. And finally, though our orientation is historical, we are open to studies that help us build a better understanding of the present state of sustainable design and suggest directions for the future.