"The Harpies of Madrid, or the Post Horse From the Spanish work of the author Donna Rufina" is an exciting adventure novel by the author Alonso de Castillo Solorzano, which tells the story of the mysterious and at the same time vulnerable harpies who spread panic among the residents of Madrid. The main character embarks on a dangerous journey in a mail box to find a way to overcome this mysterious threat. The book captivates with its intense atmosphere, unexpected plot twists and a subtle combination of magic and realism. "The Harpies of Madrid, or The Post Horse" is a work that will definitely keep you on the edge of your seat until the last page.