In the Middle Ages, the heretic, more than any other social or religious deviant, was experienced as an imaginary construct. Everyone believed heretics existed, but no one believed himself or herself to be a heretic, even if condemned as such by representatives of the Catholic Church. Those accused of heresy, meanwhile, maintained that they were the good Christians and their accusers were the false ones. Exploring the figure of the heretic in Catholic writings of the twelfth and thirteenth centuries as well as the heretic's characterological counterpart in troubadour lyrics, Arthurian romance, and comic tales, seeks to understand why French literature of the period celebrated the very characters who were so persecuted in society at large. Karen Sullivan proposes that such literature allowed medieval culture a means by which to express truths about heretics and the epistemological anxieties they aroused. The first book-length study of the figure of the heretic in medieval French literature, explores the relation between orthodoxy and deviance, authority and innovation, and will fascinate historians of ideas and literature as well as scholars of religion, critical theory, and philosophy.