Design has been a key protagonist in the story of the ¿Sustainability Project.¿ Yet, with capitalism, emissions, biodiversity loss and social injustice increasing, it might be argued that `the project,¿ and design¿s role in it, have failed to engender the sustainable transitions the planet and its people urgently require ¿ and indeed deserve. This theme track aims to counter this defeatist narrative. Emphasising the ever-evolving relationship between Design and Sustainability, the track reflexively recognises that although design can often find itself a main driver of environmental unsustainability, it can similarly be harnessed as a critical conduit for positive planetary change. This theme thusly brings together 12 papers that evidence and negotiate this inherent duality and complexity. Exploring design and sustainability through a plurality of perspectives, the papers illustrate that the ¿Sustainability Project¿ gallantly endures. By embracing newer worldviews, tools and techniques such as More-than-Human Design, Regenerative Design and Participatory Futuring, design-oriented planetary researchship continues to be a highly valuable research endeavour into the 21st century.