The best source for information on Dorothy Day is the Catholic Worker website.
Some of her description of her mentor, Peter Maurin:
Peter made you feel a sense of his mission as soon as you met him. He did not begin by tearing down, or by painting so intense a picture of misery and injustice that you burned to change the world. Instead, he aroused in you a sense of your own capacities for work, for accomplishment. He made you feel that you and all men had great and generous hearts with which to love God. If you once recognized this fact in yourself you would expect and find it in others. [p. 171]