"The Great Keinplatz Experiment and Other Tales of Twilight and the Unseen" by A. Conan Doyle is a collection of short stories written in the early 20th century. This anthology explores themes of the supernatural, psychology, and the unseen forces that shape human experience. The stories delve into encounters with ghosts, inexplicable phenomena, and psychological mysteries, often featuring characters such as doctors, scientists, and individuals grappling with the unknown. The opening of the book introduces us to Dr. Hardacre, who becomes heir to his wealthy uncle, Sir Dominick Holden, a once-famous Indian surgeon. As Hardacre visits his uncle's estate, he learns of a haunting experience that has plagued Sir Dominick for years: an apparition of a one-handed Indian man who seeks the return of his hand. As the two men discuss this strange phenomenon over dinner, Sir Dominick reveals that this torment has turned him into a nervous wreck, prompting Dr. Hardacre's curiosity and his decision to stay the night in order to confront the haunting. The narrative sets the stage for an exploration of the intersection between science and the supernatural, as well as the psychological impact of fear and the unknown. (This is an automatically generated summary.)