Mother Catherine Spalding (1793--1858) was the cofounder and first leader of one of the most significant American religious communities for women -- the Sisters of Charity of Nazareth near Bardstown, Kentucky. Elected at age nineteen to lead the order, Spalding also founded several educational institutions, Louisville's first private hospital, and the first social service agency for children in Kentucky. Pioneer Spirit is the first biography of Catherine Spalding, a woman who made it her life's work to serve the citizens of the Kentucky frontier. Catherine, who lost her mother at a young age and was raised in many different homes before she was ten years old, eventually came to be raised in a colony of Catholic families. These formative years taught her independence, the value of hard work and an enduring spirit, and the importance of education, all of which would figure prominently in her later career. Spalding became increasingly interested in health care, services for orphans, and education, and her business skills and strong sense of purpose allowed her to achieve her goals with little interference from outsiders. She showed a natural gift for administration, and the scope and services of the Sisters of Charity expanded under her leadership. In the midst of this ministerial work, however, Spalding always maintained the connection of her ministry to spiritual and communal life, ascribing great importance to all three facets of her calling. Author Mary Ellen Doyle notes that in Spalding's correspondence with the Sisters, she repeatedly emphasized the heart of charity: "genuine interest in each other and sisterly affection free of personal ambition or jealousy." By the time of Catherine Spalding's death, the Sisters of Charity of Nazareth extended beyond Nazareth to more than one hundred sisters in sixteen convents. Spalding's legacy of service continues today with more than six hundred members worldwide, and her story of progressive and compassionate leadership offers unique insights into the growth of a religious order and the struggles of developing America's frontier communities.