Scholars and activists mobilize increasingly the term degrowth when producing knowledge critical of the ideology and costs of growth-based development. Degrowth signals a radical political and economic reorganization leading to reduced resource and energy use. The degrowth hypothesis posits that such a trajectory of social transformation is necessary, desirable, and possible; the conditions of its realization require additional study. Research on degrowth has reinvigorated the limits to growth debate with critical examination of the historical, cultural, social, and political forces that have made economic growth a dominant objective. Here we review studies of economic stability in the absence of growth and of societies that have managed well without growth. We reflect on forms of technology and democracy compatible with degrowth and discuss plausible openings for a degrowth transition. This dynamic and productive research agenda asks inconvenient questions that sustainability sciences can no longer afford to ignore.