Catherine McAuley (1778-1841) founded the Sisters of Mercy in Dublin in 1831. Her letters are essential primary sources for readers interested in the life and works of this remarkable Irish churchwoman and in women's history and Irish church history more broadly. Whether McAuley is writing to family members, bishops, her solicitor, priests, lay coworkers, or Sisters of Mercy in Ireland and England, her letters reveal striking details about the church and society of her day as well as about her own spiritual convictions and unstinting personal service to poor, sick, homeless, or uneducated adults and children. documented edition of more than 320 surviving letters written by, to, or about McAuley during her lifetime. Drawn from archives worldwide and arranged chronologically, the letters are carefully transcribed and generously annotated, with brief narratives introducing each group. In her letters as well as in those of the other correspondents, one sees a delightfully human, affectionate woman; a compassionate, persistent servant of the poor and neglected; an astute businesswoman; and an unpretentious, humorous friend. readers and demonstrates not only her important role in the founding and amazing spread of the Mercy congregation in her lifetime (now numbering more than 10,000 members globally), but also her personal contributions to the pastoral development of the church in Ireland and England. Scholars and other readers will gain fresh insights into many prominent ecclesial leaders in the years 1828-1841, including Daniel Murray, archbishop of Dublin, and Thomas Griffiths, vicar apostolic of the London District. They will also find in these engaging letters one woman's grass-roots experience of certain social, economic, and ecclesiastical arrangements of her time and place.