Your search for "Mary Shelley" revealed the following:
2004, 20th Printing, Trade Softcover. Very Good. No markings. A book beloved by Arthur Conan Doyle and one often compared to Mary Shelley's "Frankenstein," this Victorian classic will haunt the canon forever.
1986, Trade. Very Good. Unread. Cover shows light wear and is lightly sunned. This collection contains "The Castle of Otranto" by Horace Walpole, "Vathek" by William Beckford and, of course, "Frankenstein" by Mary Shelley