[Excerpt] The essays presented here examine the emergence, successes, and failures of contemporary urban-based labor movements, especially in the United States, where such developments are most significant, but also in the United Kingdom and Germany in comparative perspective. Our central question is why such labor movements have emerged prominently and achieved significant successes in some cities but not in others. A comparative analysis points to the central role of two factors: agency, specifically the choices and strategies pursued by union leaders and their organizations; and opportunity structure, located in the presence or absence of particular barriers in the institutional, political, and social context. Although opportunity is important, we also find contrasting outcomes for local labor movement influence given similar opportunities and similar outcomes given contrasting opportunities. Innovative strategies offer potential for strengthening labor's urban-level influence in any circumstances.