This book argues that women writers of the French eighteenth century claimed reason and contributed to Enlightenment. Eighteenth-century French thinkers in diverse fields repeatedly proclaimed that the light of reason becomes distorted when it passes through the lens of femininity. Women writers challenged this stereotype. Engaging both canonical and non-canonical authors, this study focuses on works by Franæoise de Graffigny, Marie Jeanne Riccoboni, and Isabelle de Charrière. It treats texts across genres, ranging from their well-known novels to little-known, unpublished manuscripts. The book examines the fiction of Enlightenment in two senses: first, works of fiction can illuminate Enlightenment; second, current understandings of Enlightenment are fictional to the extent that they overlook women's works. Faithful to the eighteenth century, this study is also relevant to the twenty-first. It asks: How would current understandings of the French Enlightenment change if women's intellectual contributions were taken seriously?