The first book-length study of Horace Walpole's scandalous The Mysterious Mother, including critical essays, an abridged script, and a facsimile edition Horace Walpole's five-act tragedy The Mysterious Mother (1768), a sensational tale of incest and intrigue, was initially circulated only among the author's friends. Walpole never permitted it to be performed during his lifetime except as a private theatrical. He described his play as a "delicious entertainment for the closet" and claimed that he "did not think it would do for the stage." Yet the essays in this volume trace a history of private readings, amateur theatricals, and even early public performances, demonstrating that the play was read and performed more than Walpole's protests suggest. Exploring a wide variety of topics--including the play's crypto-Catholicism, its treatments of incest, guilt, motherhood, orphans, and scientific spectacle, and the complex relations between print and performance--the essays demonstrate the rich relevance of The Mysterious Mother to current critical discussions. The volume includes the proceedings of a mini-conference hosted at Yale University in 2018 on the occasion of a staged reading of the play. Also included are the director's reflections, an abridged script, a facsimile of Walpole's own copy of the full-length play, and reproductions of the illustrations he commissioned from Lady Diana Beauclerk.