[2][3] De León, a professor of anthropology at the University of California, Los Angeles and also the founder of the Undocumented Migration Project, conducted ethnographic research across Mexico for seven years to learn more about and speak with smugglers who moved migrants through the country, specifically in a post-Programa Frontera Sur landscape.

[4] Among other locations, De León's investigation happened in Chiapas, on the border of Guatemala, where many smugglers operate in order to move migrants along the dangerous, treacherous path from Honduras to the United States.

"[7] In a third starred review, Library Journal stated that "De León vividly depicts how both groups are part and parcel of a dangerous global industry in pursuit of greater economic opportunity.

"[8] Jennifer Szalai, for the New York Times, lauded De León for the nuance and transparency he showed to the reality of immigration, as well as his skillful synthesis of oral history resulting from his ethnographic research.

Szalai in particular highlighted the candidness of De León's testimonies: "his subjects start to trust him and begin to reveal themselves—no small feat, considering that suspicion and mistrust are a matter of professional (and physical) survival.