When it comes to Gothic fiction, Walpole (later in his life the Earl of Orford) is The Man—his clumsy and over-the-top (at least to most modern readers) melodramatic thriller The Castle of Otranto, published on Christmas Eve in 1764 (the year in which James Watt perfected the steam engine, thus laying the groundwork for the Industrial Revolution), more-or-less began the Gothic as we know it. Initally accepted rather favorably, Otranto was villified by the press once it was revealed, in the second edition, that the work was not in fact a translation of an old manuscript but the contemporary creation of the politically and socially well-connected son of a Prime Minister. Walpole's drama The Mysterious Mother, never performed in his lifetime, dealt with another topic that would attract much (scandalized) attention in the Romantic period: incest.
The Library—a collection of Horace Walpole stuff (editions, MSS, etc) and materials related to British culture in the Georgian period—sounds fascinating, though the website is largely descriptive, offering no access to any of the textual holdings, although many digital images from the collection are now available. [Yale U]
"BAC" being the British Arts Center at Yale U; this brief article from the Yale Herald (Yale's undergraduate newspaper) discusses, in interesting terms, a 1999 exhibit of materials from the Lewis Walpole Library. [Bidisha Banerjee, Yale Herald Online]
Self-described as "dedicated to promoting this fragile and unique house to the wider world, and to help it survive into the future." Great resource for info about Wapole's classic architectural creation.
The title-page of the first edition of this work originally read as follows: The Castle of Otranto, A Story. Translated by William Marshal, Gent. From the Original Italian of Onuphrio Muralto, Canon of the Church of St. Nicholas at Otranto." For the second edition the subtitle became "A Gothic Story" and the pose of a translator/source was dropped.
In Czech, with Japanese subtitles at this website. Plot summary at IMDB.com....
Not directly Gothic, but Walpole was a prodigious writer of letters, corresponding with many of the most important cultural and political figures of his time, and there are some nuggets worth mining for. There are volumes of letters available at Project Gutenberg, each as an individual file:
Walpole's drama on that popular yet disturbing theme oddly common in the Romantic period: incest. Wapole gives us a multiple incest scenario: the Countess knowingly seduces her son on the night of her husband's death; her son, Edmund, thinks he's having sex with one of his mother's maids, so he's pretty much guiltless. This tryst makes the Countess pregnant, and she gives birth to Adeliza, with whom Edmund, not knowing she is the Countess' daughter (let alone not knowing that she is also his own daughter and his half-sister), falls in love. They marry, and only then does the Countess, who's been laboring under a load of guilt for 16 years, reveal all. Layer onto this a plot involving the wicked and duplicitious monk Benedict, and you're in deep Gothic waters. Unlike Otranto this work is utterly devoid of supernaturalism, but with a family romance like that as the subject, who needs ghosts? Perhaps not surprisingly, the play was never performed in Walpole's lifetime.
- at GoogleBooks [efacsimile of 1791 edition]
-- Brief review of a 2001 Scottish production of the play.
For another inexpensive version of Walpole's magnum opus, you may want to consider this volume — another of those treasures edited by E. F. Bleiler and published by Dover — which features, in addition to Walpole's Castle, William Beckford's bizzare Oriental quasi-gothic tale Vathek, John Polidori's The Vampyre, and the fragmentary novel by Lord Byron said to be Polidori's inspiration/source. That's a lot of Gothic for your money, and this is a book which everyone interested in Gothic literature should own:
click for info
Then there's this collection of little-known Walpole texts, Hieroglyphic Tales published by Mercury House.