Migrants, both spatially and mentally, no longer settle in only one national territory but interact or move across borders regularly, profoundly challenging the nation-state and the image of society as a container. This volume explores the ways in which migrants, activists and professionals connect social worlds across national boundaries through a variety of social practices. The contributions from various disciplines - anthropology, economics, political and social sciences, educational studies and social work - illuminate the meaning of agency in situations where the capabilities of transnational actors are constrained by nation-states, their borders and social institutions. Based on a relational understanding of transnational agency which builds upon new insights and developments within transnational studies and network theory, this compilation of chapters presents transnational processes and developments in and across various regions of the globe - in East Asia, the Americas, the EU, Southeast Asia, Africa and Australia, in the borderlands of Mexico and the US, in the transatlantic space of the 19th-century fin de siècle world - in order to demonstrate the importance of gaining, assisting and expanding agency in transnational contexts.