Rasmus C. Beck, Dmitri Domanski, Julia Frohne

• Focusing on the implementation of the Smart Specialisation Strategy (S3), the chapter examines the development of cluster policies in the Ruhr Metropolis as a post-industrial region. The chapter traces the historical development of the Ruhr Area from its industrial peak in the 20th century to its slow transformation into a post-industrial landscape characterised by high urban density, new knowledge-based clusters and a persistent structural lack of effective regional cooperation. The analysis shows the conceptual shift from traditional cluster policies to the S3 approach, introduced by the European Union in 2014. The Smart Specialisation Strategy calls for a focus on comparative regional strengths and the involvement of a wide range of stakeholders in the identification of clusters for sustainable economic growth. The chapter also discusses the challenges and milestones in developing a coherent and effective Smart Specialisation Strategy, emphasising the need for inter-municipal cooperation and a new multi-level approach to regional governance. Using the case of the Ruhr Metropolis, the chapter highlights the opportunities and constraints of S3 policies to revitalise post-industrial regions by promoting innovation and adapting to global economic trends in cluster development, thus showing a way forward for other regions with similar structural challenges.