Book excerpt: Despite a shared interest in using borders to explore the paradoxes of state-making and national histories, historians of the U.S.-Canada border region and those focused on the U.S.-Mexico borderlands have generally worked in isolation from one another. A timely and important addition to borderlands history, Bridging National Borders in North America initiates a conversation between scholars of the continent’s northern and southern borderlands. The historians in this collection examine borderlands events and phenomena from the mid-nineteenth century through the mid-twentieth. Some consider the U.S.-Canada border, others concentrate on the U.S.-Mexico border, and still others take both regions into account. The contributors engage topics such as how mixed-race groups living on the peripheries of national societies dealt with the creation of borders in the nineteenth century, how medical inspections and public-health knowledge came to be used to differentiate among bodies, and how practices designed to channel livestock and prevent cattle smuggling became the model for regulating the movement of narcotics and undocumented people. They explore the ways that U.S. immigration authorities mediated between the desires for unimpeded boundary-crossings for day laborers, tourists, casual visitors, and businessmen, and the restrictions imposed by measures such as the Chinese Exclusion Act of 1882 and the 1924 Immigration Act. Turning to the realm of culture, they analyze the history of tourist travel to Mexico from the United States and depictions of the borderlands in early-twentieth-century Hollywood movies. The concluding essay suggests that historians have obscured non-national forms of territoriality and community that preceded the creation of national borders and sometimes persisted afterwards. This collection signals new directions for continental dialogue about issues such as state-building, national expansion, territoriality, and migration. Contributors: Dominique Brégent-Heald, Catherine Cocks, Andrea Geiger, Miguel Ángel González Quiroga, Andrew R. Graybill, Michel Hogue, Benjamin H. Johnson, S. Deborah Kang, Carolyn Podruchny, Bethel Saler, Jennifer Seltz, Rachel St. John, Lissa Wadewitz Published in cooperation with the William P. Clements Center for Southwest Studies, Southern Methodist University.