Christopher Morley's 1919 book The Haunted Bookshop is currently considered to be American public domain. It continues to be a well-known example of bibliomystery, a mystery novel that is set in the world of books. This thrilling book takes place in Brooklyn near the close of World War I. The narrative of Roger Mifflin, the bookseller from Parnassus on Wheels, is continued. Additionally, it describes Miss Titania Chapman and Aubrey Gilbert, a young advertising executive, on their voyage. The Haunted Bookshop is not a supernatural book. The phrase the ghosts of all great literature alludes to the historical ghosts that stalk every library and bookshop. Several times throughout the book, Morley alludes to the knowledge and wisdom that reading can provide through the persona of Roger Mifflin. Despite Morley's constant exhortations to read, this is largely a suspense tale. The main character, Mifflin, calls himself a practitioner of bibliotherapy and believes that, like doctors, booksellers can treat mental illnesses. A librocubicularist, according to Mifflin, is someone who enjoys reading in bed. Gilbert and Mifflin discover the real plot in the book's final chapter, which goes as follows: The bookshop had been the drop-off location for the German spy who worked as a pharmacist.