Carolyn Hart 
From the Queen [EPUB ebook] 

All book lovers dream of stumbling upon a long-lost treasure in the attic or inheriting a fortune from a distant relative. For Ellen Gallagher, the impoverished owner of a thrift store in South Carolina, the dream comes true when she finds in her possession a first edition of Agatha Christie’s Poirot Investigates that has been signed by the author and inscribed to the Queen of England. When this extraordinary book mysteriously disappears from her shop, Ellen calls on her friend Annie Darling, owner of the Death on Demand mystery bookstore, to track down the stolen volume. But Annie’s persual of the book leads her to grave danger as in order to recover her friend’s prized possession, she must meet Death face to face.