For instance, there is Miguel, who was found wandering, disoriented, near Casa Juan Diego, with a deep gash on the side of his head and stitches marking where his fingers used to be. He’d been trimming a tree with a chainsaw when he fell. At least his employer had taken him to the hospital. Other worksite accident victims were not always so lucky, the Zwicks write.

Many – like Vidal, who lost both hands and a foot after his metal ladder touched some live wires – were simply dropped off at Casa Juan Diego by their employers, who then disappeared. And then there are the workers, usually at least one per week, who show up at Casa Juan Diego’s door black and blue – or worse – from being robbed.

For female immigrants, their only chance at employment may be live-in-housework and child care – sometimes six or seven days a week. Sadly, there are always people ready to exploit them, the Zwicks report. Rita, who worked as a baby sitter for an American couple’s children, was fired for theft she had not committed, after she told the wife about the husband’s unwelcome sexual advances. Another immigrant domestic worker, Mercedes, was wrongfully accused of stealing jewelry from her employer’s home and fired. Even though the jewelry was later found, the employer never withdrew the police report she had made.

The Houston Catholic Worker also is a beacon for the homeless who may suffer from mental illness, perhaps hearing voices that are not there. With so many people in need coming and going, how does Casa Juan Diego maintain its peace and equilibrium? The authors point to the freedom of the Gospel as their inspiring compass. Such freedom “is quite different from rugged individualism or doing whatever we want,” they write. “The freedom of the Gospel is not about buying ourselves things nor about building bigger banks to hold our money, nor about arming ourselves to the teeth to protect it.”

Rather, it is the freedom “to do good, to create a world where it is easier for others to be good.” Catholic Worker “personalism” means that “Catholics do not have to wait for orders from Rome to begin washing others’ feet. … We are free to love our enemies. We are free to develop alternatives to an economy that takes away the dignity and the meaning of work. We are free to help the stranger in a strange land. … We are free to give up all and follow Jesus.”

Truly, those at Casa Juan Diego are able to recognize Christ’s face in their homeless and forgotten visitors. This account of their work engagingly blends personal stories and sharp analysis, culled from the trenches, about the problems underlying immigration. While the storytelling in “Mercy Without Borders” invites quick reading, the ethical and social questions it raises will compel thought long afterward.

Roberts directs the journalism program at the State University of New York at Albany. Her books include “Dorothy Day and the Catholic Worker.”