The book's title derives from a speech given by Holmes, a consulting detective, to his friend and chronicler Watson on the nature of his work, in which he describes the story's murder investigation as his "study in scarlet": "There's the scarlet thread of murder running through the colourless skein of life, and our duty is to unravel it, and isolate it, and expose every inch of it.

Eleven complete copies of the magazine in which the story first appeared, Beeton's Christmas Annual for 1887, are known to exist now, which have considerable value.

[2] 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 victim is Enoch Drebber of Cleveland, Ohio, and documents found on his person reveal that he has a secretary, Joseph Stangerson.

On one wall, written in red, is "RACHE" (German for "revenge"), which Holmes dismisses as a ploy to fool the police.

Hope breaks into Drebber's house the night before Lucy's funeral to kiss her body and remove her wedding ring.

He swears vengeance on Drebber and Stangerson but begins to suffer from an aortic aneurysm, causing him to leave the mountains to earn money and recuperate.

Hope then takes him to the house on Brixton Road and forces Drebber to recognize him and to choose between two pills, one of which is harmless and the other poison.

The excitement coupled with his aneurysm causes his nose to bleed; he uses the blood to write "RACHE" on the wall above Drebber to confound the investigators.

[4] As a doctor in general practice in Southsea, Hampshire, he had already published short stories in several magazines of the day, such as the periodical London Society.

The story was originally titled A Tangled Skein and was eventually published by Ward, Lock & Co. in the 1887 edition of Beeton's Christmas Annual, after many rejections.

The novel was first published as a book in July 1888 by Ward, Lock & Co, and featured drawings by the author's father, Charles Doyle.

According to a Salt Lake City newspaper article, when Conan Doyle was asked about his depiction of the Latter-day Saints' organisation as being steeped in kidnapping, murder and enslavement, he said: "all I said about the Danite Band and the murders is historical so I cannot withdraw that, though it is likely that in a work of fiction it is stated more luridly than in a work of history.

"[6] Conan Doyle's daughter has stated: "You know, father would be the first to admit that his first Sherlock Holmes novel was full of errors about the Mormons.

Years after Conan Doyle's death, Levi Edgar Young, a descendant of Brigham Young and a Mormon general authority, alleged that the author had privately apologised, saying that "He [Conan Doyle] said he had been misled by writings of the time about the Church"[6] and had "written a scurrilous book about the Mormons.

"[7] In August 2011, the Albemarle County, Virginia, school board removed A Study in Scarlet from the district's sixth-grade required reading list following complaints from students and parents that the book was derogatory toward Mormons.

In the film, titled A Study in Scarlet, Holmes was played by James Bragington, an accountant who worked as an actor for the only time of his life.

[12] The 1933 film titled A Study in Scarlet, starring Reginald Owen as Holmes and Anna May Wong as Mrs Pyke, bears no plot relation to the novel.

[14] Edith Meiser adapted A Study in Scarlet into a four-part serial for the radio series The Adventures of Sherlock Holmes.

[16] The story was adapted for the 1952–1969 BBC radio series in 1962 by Michael Hardwick, with Carleton Hobbs as Holmes and Norman Shelley as Watson.

[17] Another British radio version of the story adapted by Hardwick aired on 25 December 1974, with Robert Powell as Holmes and Dinsdale Landen as Watson.

The cast also included Frederick Treves as Gregson, John Hollis as Lestrade, and Don Fellows as Jefferson Hope.

The 1954–1955 television series (with Ronald Howard as Holmes and H. Marion Crawford as Watson) used only the first section of the book as the basis for the episode "The Case of the Cunningham Heritage".

[22] The book was adapted into an episode broadcast on 23 September 1968 in the second season of the BBC television series Sherlock Holmes,[23] with Peter Cushing in the lead role and Nigel Stock as Dr Watson.

[25] The adaptation retains many individual elements from the story, such as the scribbled "RACHE" and the two pills, and the killer's potentially fatal aneurysm (although it is located in his brain rather than his aorta).

They find out that a pupil called Jefferson Hope has taken revenge on Enoch Drebber and Joseph Stangerson for stealing his watch.

[28] In 2014, A Study in Scarlet was adapted for the stage by Greg Freeman, Lila Whelan and Annabelle Brown for Tacit Theatre.

[30] In February 2019, a new adaptation of "A Study in Scarlet" was staged at DM Performance Works at the Factory in Nuremberg, PA.

Rather than a Mormon that forced a woman into an abusive marriage and was killed for it, Drebber is instead a brilliant scientist and engineer who worked on a device to get revenge on the man that ruined his life.