Mary Ann Bickerdyke led a remarkable life. A widowed mother from Illinois, she became an influential traveling nurse and Sanitary Commission agent during the American Civil War. She followed the Union Army through four years and nineteen battles, established hundreds of hospitals, assisted surgeons with amputations, treated fevers, and fed the soldiers in her care. Known affectionately as "Mother" to thousands of soldiers, Bickerdyke's work bridged the private world of home caregiving and the public demands of wartime and institutional medicine. Drawing on a rich archive of personal letters, military records, and newspapers, Megan VanGorder explores how Bickerdyke used her maternal identity to challenge norms, advocate for soldiers, and pioneer compassionate care practices before, during, and after the Civil War. A Mother's Work uses key episodes from Bickerdyke's life to reveal broader truths about motherhood, medicine, and women's roles in the nineteenth century, and offers an intimate and historically grounded portrait of one woman's evolving identity and the use of the moniker that made her famous. In reassessing her work and legacy, this book also serves as a new perspective on how white working-class women contributed to the transitional period of the Civil War era to reshape public health, social care, and national memory.