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.
SHERLOCK HOLMES—his limits.
1. Knowledge of Literature.—Nil.
5. Botany.—Variable. Well up in belladonna,
opium, and poisons generally.
Knows nothing of practical gardening.
6. Geology.—Practical, but limited.
Tells at a glance different soils
from each other. After walks has
shown me splashes upon his trousers,
and told me by their colour and
consistence in what part of London
he had received them.
8. Anatomy.—Accurate, but unsystematic.
9. Sensational Literature.—Immense. He appears
to know every detail of every horror
perpetrated in the century.
10. Plays the violin well.
11. Is an expert singlestick player, boxer, and swordsman.
12. Has a good practical knowledge of British law.
reference : Wikipedia, A Study in Scarlet
The story is set in 1888.
The Sign of the Four has a complex plot involving service in East India Company, India, the Indian Rebellion of 1857, a stolen treasure, and a secret pact among four convicts ("the Four" of the title) and two corrupt prison guards. It presents the detective's drug habit and humanizes him in a way that had not been done in the preceding novel, A Study in Scarlet (1887). It also introduces Doctor Watson's future wife, Mary Morstan.
Sir Arthur Conan Doyle described how he was commissioned to write the story over a dinner with Joseph M. Stoddart, managing editor of an American publication Lippincott's Monthly Magazine, at the Langham Hotel in London on 30 August 1889. Stoddart wanted to produce an English version of Lippincott’s with a British editor and British contributors. The dinner was also attended by Oscar Wilde, who eventually contributed The Picture of Dorian Gray to the July 1890 issue. Doyle discussed what he called this "golden evening" in his 1924 autobiography Memories and Adventures.
The novel first appeared in the February 1890 edition of Lippincott's Monthly Magazine as The Sign of the Four; or The Problem of the Sholtos (five-word title), appearing in both London and Philadelphia. The British edition of the magazine originally sold for a shilling, and the American for 25 cents. Surviving copies are now worth several thousand dollars.
Over the following few months in the same year, the novel was then republished in several regional British journals. These re-serialisations gave the title as The Sign of Four. The novel was published in book form in October 1890 by Spencer Blackett, again using the title The Sign of Four. This edition was illustrated by Charles H. M. Kerr. The title of both the British and American editions of this first book edition omitted the second "the" of the original title.
Different editions over the years have varied between the two forms of the title, with most editions favouring the four-word form. The actual text in the novel nearly always uses "the Sign of the Four" (the five-word form) to describe the symbol in the story, although the four-word form is used twice by Jonathan Small in his narrative at the end of the story.
As with the first story, A Study in Scarlet, produced two years previously, The Sign of the Four was not particularly successful to start with. It was the short stories, published from 1891 onwards in Strand Magazine, that made household names of Sherlock Holmes and his creator.
reference : Wikipedia, The Sign of the Four
The novel starts when Sherlock Holmes receives a mysterious ciphered message from an agent to Professor Moriarty using the pseudonym Fred Porlock. Together Holmes and Watson decipher Porlock's message which relates that a man named John Douglas, residing at Birlstone, is in danger. Soon inspector Alec MacDonald of Scotland Yard ask Holmes to help in the case. Holmes tells MacDonald of Porlock warning, suggesting Professor Moriarty's involvement. However, MacDonald doesn't fully believe that the educated and well respected Moriarty is a criminal.
Holmes, Watson, and MacDonald travel to Birlstone, Sussex, where they investigate the old manor with a moat where Douglas was shot. They meet Cecil Barker a regular guest of the Douglas. They also find a sawed-off shotgun and evidence suggesting that it was fired at close range, causing the head to be blown to pieces. Holmes explores Barker's claims that he was in his room when Douglas was shot. Moreover, they find a mark of blood upon the window sill suggesting someone entered and escaped by going through the moat. Beside the body they find a card with the initials "V.V. 341", and on Douglas's arm an old branded mark. Moreover, Douglas' wedding ring appears taken from his hand.
The police speculate that if the murderer must have escaped across the moat, but if this was so then the question of his clothes were wet as he walked through the town. Holmes establishing the timeline of events through interviews: Cecil Barker heard the shot, rushed down to the study and upon seeing Douglas murdered he rang the servants. Mrs. Douglas and the servants rushed to the scene. Mr. Barker persuades Mrs. Douglas to return to her room. Holmes notes Mrs. Douglas apparent lack of emotion over her husband's body.
Barker says that he believes a secret society of men pursued Douglas, and that Douglas retreated to rural England out of fear for his life. Mr. Douglas married after arriving in England five years earlier. His first wife had died of typhoid. Douglas met and worked with Cecil Barker in America, before departing for Europe. Some episode of Douglas's life in America caused the fear for his life, and Mrs. Douglas said her husband mention something called "The Valley of Fear".
By studying Cecil Barker's slippers, Holmes determines Barker's shoe made the mark on the window, to give the appearance that someone exited that way. In their lodgings, Holmes tells Watson that Cecil Barker and Mrs. Douglas are certainly lying: when a shotgun is fired at close range, the sound is muffled. Moreover, Holmes learns that the housekeeper heard a door slamming half an hour before the alarm, which Holmes believes was actually the murdering shot. White Mason, the Sussex detective, and MacDonald track a bicycle found on the grounds of the house to an American staying at a guest house. The American appears to be the murderer, but there is no sign of the man.
Holmes ask MacDonald to write Cecil Barker, telling him that the police intend to search the moat the next day. That night Holmes, Watson, MacDonald and White lay in wait outside Birlstone Manor and see Cecil Barker fish something out of the moat. The four men rush Cecil and discover the bundle from the moat is the clothes of the missing American connected with the bicycle. Barker refuses to explain the situation. At that moment, Mr. Douglas appears, alive and well. He hands Watson a written account called "The Valley of Fear", which explains why he feared for his life.
Douglas explains that he had spotted an enemy of his, Ted Baldwin, in the area and expected an attack. When Baldwin attempted to shoot him in his study, Douglas grabbed the gun and shoots Baldwin in the face. With Cecil's help, Douglas dressed the man in his own clothes, except for his wedding ring, to deceive the secret society which he and Baldwin had belong too, since both arms bore the society's Mark. Cecil and Mrs. Douglas had covered for Douglas who had been hiding in the house. In an interview with Watson, Douglas explains that his real name was Birdy Edwards acting as Pinkerton detective in Chicago. For the agency Edwards infiltrated a dangerous gang in Vermissa Valley (a.k.a. the Valley of Fear) and brought them to justice. Afterwards, the criminals attempted to kill him, after being released from jail.
Hounded Douglas had run to England, where he met and married his second wife. Holmes urges Douglas to leave England and warns that a new threat now hangs over him. Douglas takes this advice, but shortly after Holmes learns that Douglas was lost overboard on the vessel to Africa. Holmes believes Moriarty was responsible for ending Douglas' life. Holmes wants to bring Moriarty down, but warns Watson and Barker that it will take some time to achieve.
reference : Wikipedia, The Valley of Fear