Between deep roots and a broad crown: reflections on the development of sustainability transitions as a research field

In the final chapter of this handbook, we reflect on the development of sustainability transitions research (STR) as a research field by examining its origin and core focus, its achievements and current developments, as well as key critiques and future avenues. Using the metaphor of a tree, we argue that STR has grown from deep roots in various academic disciplines to develop a broad crown of research branches, all connected by a shared focus on socio-technical change processes. The rapid expansion of the research field brings opportunities as well as challenges. While STR's common language has facilitated interaction across disciplines with a shared agenda, it also risks creating rigidity and exclusivity pointing to a tension between cohesion versus fragmentation. Additionally, dissemination of findings from within STR into its foundational disciplines, as well as the growing political and social responsibilities are key challenges of STR. Overall, the field forms a robust community while holding important areas for improvement and critical (self-)reflection. Rather than definitively characterizing STR's trajectory, our aim is to foster the conversation about the field's perceived development and future directions, recognizing that like a tree, research fields require continuous nurturing and exchange to remain vital and productive.