This study examines a seventeenth-century episode of Catholic spiritual guidance, centered on the relationship between Gaston de Renty and Élisabeth de la Trinité between 1643 and 1649. Bernard Pitaud reconstructs the development, tensions, and religious significance of this direction spirituelle within the spiritual culture of early modern France. Drawing on the lives of two notable Catholic figures, the book places personal devotion, ecclesiastical expectations, and the practice of spiritual accompaniment in their historical context. It is a work of religious history that illuminates how spiritual authority, conscience, and reform-minded Catholic life intersected in the seventeenth century.