Barbara Leavy has written three books on supernatural femmes fatales and demon lovers in folklore and literature, the last of which, reviewed favorably by The New York Times Sunday Book Review, is In Search of the Swan Maiden: A Narrative on Folklore and Gender. Her book on epidemic diseases as a literary subject, To Blight with Plague, paved the way for her analysis of how Ruth Rendell treats disease as a theme in her fiction. In the field of mystery writing, her study of The Woman in White and the history of psychology in nineteenth-century England is a resource for Wilkie Collins scholars.