The Sign of the Four
Doyle was reputedly commissioned to write the story over an August 30, 1889, dinner with Joseph M. Stoddart, managing editor of Lippincott's Monthly Magazine, at the Langham Hotel in London. 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 (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 re-published in several regional British journals. These re-serialisations gave the title as The Sign of Four (four-word title).
The novel was published in book form in October 1890 by Spencer Blackett, again using the title The Sign of Four. The title of both the British and American editions of the this first book edition omitted the second "the" of the original title.
Different editions over years have varied between using one or the other title, with most editions favoring the four-word form. The actual text (as opposed to the title) of the novel always uses "the Sign of the Four" (the five-word form) to describe the symbol in the story.
As with the first story, A Study in Scarlet, produced two years previously, it was not particularly successful to start with. It was the short stories which were published from 1891 onwards in Strand Magazine which rapidly made Sherlock Holmes and his creator household names.
Set in 1887 or 1888; The Sign of Four has a complex plot involving service in colonial India, a stolen treasure and a secret pact among four ex-convicts. It presents the detective's drug habit and humanizes him in a way that had not been done in the first novel, A Study in Scarlet. It also introduces Doctor Watson's future wife, Mary Morstan.
* The Sign of Four is the title of an album by guitarists Derek Bailey and Pat Metheny.
* In January 2007, a character based on Tonga, one of the villains in the novel, was one of the villains in the serial "Stickleback" in the British comic 2000 AD.