This innovative book develops an integrated analytical lens for studying state and civil society interactions in migration policymaking. Maria Schiller highlights the key factors shaping the dynamics between state and civil society relations: efforts to balance power asymmetries, building trust and creating shared ideas and visions of migration-related diversity. Drawing on Robert Agranoff's concept of 'collaborarchy', the book conceptualizes the relations between state and civil society as fluid, spanning a continuum between collaboration and conflict. Bridging urban social movement and governance theories, this concept is explored in case studies such as the top down approach to managing civil society in Rotterdam and building an urban diversity alliance in Mannheim. The book expands its study outside of single actors and structural factors, illustrating how actor relationships are an important predictor for local migration and diversity policymaking. This insightful book is a key resource for students and scholars of politics and public policy, sociology, urban and regional studies and migration studies. It is also beneficial for practitioners in migration, diversity, civic participation and urban governance seeking a deeper understanding of the relations between state and civil society in immigrant policymaking.