British Library Collection: The Mysteries of Udolpho
https://www.bl.uk/collection-items/the-mysteries-of-udolpho
This webpage contains some information about the novel, its publication history, as well as images and original illustrations from an 1803 edition of the novel held in the British Library collection.
Gothic fiction pioneer Ann Radcliffe may have been inspired by mother-in-law
https://www.theguardian.com/books/2014/jan/30/ann-radcliffe-gothic-fiction-mother-in-law
This 2014 article describes a significant letter written by Radcliffe, which may provide insight into her biography and writing process.
The Women's Print History Project: the Enchanting Ann Radcliffe
https://womensprinthistoryproject.com/blog/post/37
This website provides a short biography of Radcliffe, as well as images of early editions and illustrations from some of her novels. The site also links to information about the print history of Radcliffe's novels, including The Mysteries of Udolpho.
Emily's Journey in The Mysteries of Udolpho
This website maps potential locations according to the travels Emily undergoes in the novel.
Elements of the Gothic Novel
This website provides a useful overview of the most common characteristics associated with the Gothic novel.