Book excerpt: The city as an independent subject of theorisation and investigation is an underexamined area of constitutional law. Although in recent years scholars have started to explore the legal dimension and place of urban areas, the study of cities as constitutional subjects remains very new, with a solid theoretical foundation yet to be established. Against this backdrop of general under-theorisation of cities in constitutional law and federalism, Cities in Federal Constitutional Theory seeks to offer a fresh theoretical account of cities as federalism subjects, exploring the increased importance they have acquired from political, economic, socio-cultural, and demographic perspectives. This volume directly addresses the relationship between cities, federalism, and localism (or subsidiarity), and responds to concerns about the scarcity of innovative theoretical discussion on the topic, while at the same time redefining accepted concepts like subsidiarity. Bringing together theoretical reflections on the city from established scholars, this edited collection significantly enriches the field of federal constitutional theory.