The story, and its main characters, attracted little public interest when it first appeared. Only 11 complete copies of the magazine in which the story first appeared, "Beeton's Christmas Annual" for 1887, are known to exist now and they have considerable value. Although Conan Doyle wrote 56 short stories featuring Holmes, "A Study in Scarlet" is one of only four full-length novels in the original canon. The novel was followed by "The Sign of the Four", published in 1890. "A Study in Scarlet" was the first work of detective fiction to incorporate the magnifying glass as an investigative tool.