First published pseudonymously in 1764, The Castle of Otranto purported to be a translation of an Italian story from the time of the crusades. In it, Walpole attempted, as he declared in the Preface to the second edition, "to blend the two kinds of romance: the ancient and the modern."

He presents a series of catastrophes, ghostly interventions, revelations of identity, and exciting contests. Crammed with invention, entertainment, terror, and pathos, the novel was an immediate success and Walpole's own favorite among his numerous works.

His friend, the poet Thomas Gray, wrote that he and his family, having read Otranto, were now "afraid to go to bed o'nights." This novel is reprinted from a text of 1798, the last that Walpole himself prepared for the press.