The border between Canada and the United States separates political sovereignties, but not the shared themes of cultural, social, and economic history that have unfolded since the 18th century. Transnationalism brings together original works that focus on the shared histories of the United States and Canada that have over two centuries created a distinct North American identity and sensibility. Contributors explore the phenomenon of a North American history and discuss interactions between Canada and the United States from the eighteenth century to the present. Specific themes include the First Nations experience, national and North American identities and culture, social and economic cooperation, and issues of security and defence. Transnationalism challenges us to put the border in context order to better understand the past, present, and future interrelationships between Canada and the United States.