This chapter provides an overview of the book’s organizing theoretical framework, the Identity Mobilization Model, includes an overview of the sites where fieldwork for the book was conducted, and details the histories of the three subgroups whose experiences are the main focus of the book. The Identity Mobilization Model combines social movement research on education, strategy, and allyship to explain how members of a marginalized group who do not hold formal recognition under the law contest this form of exclusion and fight for increased rights. The discussion of the book’s multisited ethnographic approach, which is based on fieldwork conducted in San Francisco, Chicago, and New York City, highlights the similarity of each city with regard to the welcoming environment it provides for undocumented community members. The chapter concludes with a detailed background of the three subgroups within the immigrant rights movement that the book’s ethnographic chapters focus on: Asian undocumented immigrants, undocuqueer immigrants, and formerly undocumented women.