What connects the Baltimore Washington International Airport and South Korea's Songdo International Business District? What are the cultural narratives that unfold from their bold visions of mobility and of the city in transit and transition? Put another way, what are the relations between modernity, mobile lifestyles, and urban spaces as we move deeper into what the French sociologist Marc Augé has called the age of 'supermodernity'? Perhaps more importantly, are there alternative ways of thinking about mobility and the future of society in a rapidly shrinking, globally interconnected and, at the same time, socially and culturally divided world? In their wide-ranging contributions geographers, political scientists, historians, economists, and cultural critics take a closer look at mobility in an American context (and beyond). Investigating aspects of American mobility from a decidedly transnational and transatlantic perspective, these essays conjoin in revealing mobility as a crucial constituent of what we call modernity. They also identify some of the negative consequences and challenges of mobility in an increasingly endangered global ecology.