In this introduction to the life and thought of Dorothy Day, one of the most important lay Catholics of the twentieth century, Terrence Wright presents her radical response to God's mercy. After a period of darkness and sin, which included an abortion and a suicide attempt, Day had a profound awakening to God's unlimited love and mercy through the birth of her daughter. After her conversion, Day answered the calling to bring God's mercy to others. With Peter Maurin, she founded the Catholic Worker Movement in 1933. Dedicated to both the spiritual and the corporal works of mercy, they established Houses of Hospitality, Catholic Worker Farms, and the Catholic Worker newspaper. Drawing heavily from Day's own writings, this book reveals her love for Scripture, the sacraments, and the magisterial teaching of the Church. The author explores her philosophy and spirituality, including her devotion to Saints Francis, Benedict, and Thérèse. He also shows how her understanding of the Mystical Body of Christ led to some of her more controversial positions such as pacifism. Since her death in 1980, Day continues to serve as a model of Christian love and commitment. She recognized Christ in the less fortunate and understood that to be a servant of these least among us is to be a servant of God.