Holes in the Safety Net: Federalism and Poverty explores the relationship between antipoverty programs and federalism. The introduction provides a foundation for the rest of the book through an overview of the extent and nature of poverty in the United States as well as a brief history of how welfare programs have changed over time. We are at a moment in which the basic structure of the safety net is uncertain and up for grabs. Proposals to replace existing programs with block grants or to allow states to impose tougher restrictions on welfare recipients abound, often justified using the language of federalism. This chapter introduces these challenges and then provides a roadmap of the rest of the book.