In "The Banshees of Inisherin," James Joyce is NOT an author of a book Siobhan owns. This is because James Joyce is known for works like "Ulysses" and "Dubliners," which are not typically associated with the types of books Siobhan owns in the story. Siobhan's collection seems to focus on classic and historical literature, such as works by Walter Scott, Jane Barlow, and Jane Austen, which align more closely with the themes and genres found in "The Banshees of Inisherin."