The Irish-Catholic Sisters accomplished tremendously successful work in founding charitable organizations in New York City from the Irish famine through the early twentieth century. Maureen Fitzgerald argues that their championing of the rights of the poor—especially poor women—resulted in an explosion of state-supported services and programs.

Parting from Protestant belief in meager and means-tested aid, Irish Catholic nuns argued for an approach based on compassion for the poor. Fitzgerald positions the nuns' activism as resistance to Protestantism's cultural hegemony. As she shows, Roman Catholic nuns offered strong and unequivocal moral leadership in condemning those who punished the poor for their poverty and unmarried women for sexual transgression. Fitzgerald also delves into the nuns' own communities, from the class-based hierarchies within the convents to the political power they wielded within the city. That power, amplified by an alliance with the local Irish Catholic political machine, allowed the women to expand public charities in the city on an unprecedented scale.