With the number of undocumented immigrants in the United States at an all-time high and Congressional immigration reform seemingly at a standstill, cities and states across the nation have leapt into the fray, creating a wide range of policies—some more controversial than others—to address illegal immigration within their jurisdictions. These policies, both anti- and pro-immigrant in nature, run the gamut. Some call for the involvement of city police in immigration enforcement, debates over day laborer markets, the establishment of employer sanctions laws, and the implementation of anti-immigrant ordinances. Other policies call for cities and states to declare themselves "sanctuaries" for undocumented immigrants, passing laws to extend locally-funded health care and social services, offer English language training, and improve wages and working conditions. While these state and local immigration policies continue to receive wide coverage in the popular press, they have received very little attention in the scholarly literature. This volume aims to fill the gap by offering perspectives from political scientists, legal scholars, sociologists, and geographers at the leading edge of this emerging field. Drawing on high profile case studies, the contributors seek to explain the explosion in state and local immigration policy activism, account for the policies that have been considered and passed, and explore the tensions that have emerged within communities and between different levels of government. This timely entrant into the study of state and local immigration policy also illuminates the significant challenges and opportunities of comprehensive immigration reform, highlights the range of issues at stake, and charts a future research agenda that will more deeply explore the impacts of these policies on immigrant communities.