Mary Hays, reformist, novelist, and innovative thinker, has been waiting two hundred years to be judged in a fair, scholarly, and comprehensive way. During her lifetime and long after, her role in the ongoing reformist debates in England at the end of the eighteenth century, intensified by the French Revolution, served as a lightening rod for opponents who attacked her controversial stance on women’s intellectual competence and human rights. The author’s intellectual history of Hays finally makes the case for her importance as an innovator. She was a feminist thinker who advanced notions of tolerance that included women, an educator who broke new ground for female autodidacts, a philosophical commentator who translated Enlightenment ideas for a burgeoning female audience, a Dissenting historiographer who reinvented ‘female biography,’ and a writer of deliberately experimental fiction, including the roman a clef Memoirs of Emma Courtney. The author approaches Hays from several disciplinary perspectives-historical, biographical, literary, critical, theological, and political-to elucidate the multiple ways in which Hays contributed and responded to, and influenced and was influenced by, the most significant issues and figures of her time.