Sustainablility poses profound challenges to society – and to the architecture and design disciplines. Design has conventionally been applied to expand the market for things that (over)consume material and natural resources. For those that consume design – that is, for all of us – environmental sustainability requires us to question what we produce and consume as a society, and how we impact others and future generations. For those of us that are designers – and often seen as part of the problem within discussions of sustainable development – we need to query what and how we design. This was the question at stake nearly half a century ago for a number of movements within design. Various names for such movements, such as ‘Anti-Design’, ‘Non-Plan’ and ‘Radical Design’ indicate a critique of design, planning and architecture. Radical designers mounted a critique of their own design discipline and of a societal status quo. However, rather than debate articles or academic analyses, their critique took the form of design. The contemporary challenges of sustainable development require just such criticality. Mainstream approaches, predominately based on cleaning up production processes and incentivizing ‘green’ consumption, help to mitigate the negative environmental effects of behaviors entrenched in industrialized Western societies. However, besides incremental improvements to our lives in these societies – and looking ahead to the next 50 years – we need to be able to relate to others, alternatives and futures that may be radically different than us, here and now. Today, a multitude of socially and politically-engaged designers are taking on such issues, rapidly growing beyond a minority within architectural and design disciplines – and the questions raised are relevant to the 99% of society. As in Radical Design, criticality does not have to end in polemics, in utopias or dystopias, but in giving form to critical questions: Which – or who’s – interests should be represented in design and society? Who benefits – and who profits? What might be alternatives and futures? Who designs these futures, for whom?