This book explores how "social activity" for older people is shaped in urban ageing policy in Poznan, Poland. Using interviews, observations, and policy analysis, it shows how global ageing ideas are localized through institutions, actors, and everyday practices, revealing the complexity of policy implementation. As Europe ages, cities face increasing pressure to adapt policies for older populations. This book explores how the idea of "social activity" for older people is implemented within urban ageing policy in Poznan, Poland. Drawing on extensive fieldwork, including observations and interviews, the study uncovers how global concepts like active ageing are shaped by local institutions, actors, and contexts. It adopts discursive institutionalism, actor-network theory, and the glocalization lens to examine the complexities of translating ageing policy into practice. Through a detailed case study, the book investigates how social activity is framed, organized, and experienced in a specific urban environment, revealing hidden networks and power dynamics behind seemingly ordinary events. This work contributes to critical debates on ageing, policy implementation, and local governance, offering valuable insights for scholars, policymakers, and practitioners engaged in urban social policy and gerontology. Introduction - Part I: Chapter 1. The context of social activity for older people at the local level - Part II: Chapter 2. Theoretical framework - Part III: Chapter 3. Research design - Part IV: Chapter 4. Results and conclusions Halina Nadobnik is a social policy researcher with a PhD in social sciences from the University of Economics and Business in Poznan. Her work focuses on ageing, local public policy, and the role of institutions, NGOs, and technology in shaping older people's lives. She has co-authored studies on local communities and intergenerational careers. At WZB Berlin Social Science Center, she contributes to the project "AI Ageism", examining algorithmic discrimination against older adults.