This special issue volume in the International Journal of Design is focused on theoretical investigations into social design (e.g., history, different paradigms and models), on the methodological challenges of social design (e.g., various models, frameworks and transdisciplinary, insights and crossfertilization), and on transdisciplinary examples and implementations of social design innovations. In order to enhance our understanding and development of social design across different societies, either comparative studies or case studies on newly founded social design societies are encouraged. The editors in their Introduction concludes that the papers featured in this special issue “reveals that social design has already extended the scope of design and that there are several ways to approach its form of design. Current social design practices are limited in scope in terms of their power, but social design can overcome these limits by developing richer discourses of the social by building on its own legacy, using the expertise from both worlds and joining forces between social scientists and designers, next to the other stakeholders involved in social design projects. It has already made a serious contribution to design by raising questions about the nature of “the social” as an object of design, and no doubt it has paved the way to better futures. For us the mood of this issue, then, is optimistic.”