Undocumented Saints follows the migration of popular saints from Mexico into the US and the evolution of their meaning. The book explores how Latinx battles for survival are performed in the worlds of faith, religiosity, and the imaginary, and how the socio-political realities of exploitation and racial segregation frame their popular religious expressions. It also tracks the emergence of inter-religious states, transnational ethnic and cultural enclaves unified by faith.

The book looks at five vernacular saints that have emerged in Mexico and whose devotions have migrated into the US in the last one hundred years: Jesús Malverde, a popular bandido turned saint caudillo; Santa Olguita, an emerging feminist saint linked to border women's experiences of sexual violence; Juan Soldado, a murder-rapist soldier who is now a patron for undocumented immigrants and the main suspect in the death of an eight-year-old victim known now as Santa Olguita; Toribio Romo, a Catholic priest whose ghost/spirit has been helping people cross the border into the US since the 1990s; and La Santa Muerte, a controversial personification of death who is particularly popular among LGBTQ migrants. Each chapter contextualizes a particular popular saint within broader discourses about the construction of masculinity and the state, the long history of violence against Latina and migrant women, female erasure from history, discrimination against non-normative sexualities, and as US and Mexican investment in the control of religiosity within the discourses of immigration.