Plot: While Holmes escapes boredom to a cocaine-induced haze sitting in his apartment on Baker Street, a beautiful but distressed young woman, Mary Morstan, asks for the help of Holmes and Watson. Her father vanished ten years ago. Starting six years ago she received every year from an anonymous benefactor a large precious pearl, totaling six pearls today. Now she received an invitation to meet the anonymous sender of pearls. It is an intriguing case that Holmes and Watson happily accept...
The most exciting scene of the novel is what could be called a 19th-century version of a high-speed 'car chase', except done with fast steamboats on the Thames. It has all the drapings and features one would expect in a chase scene in an action movie today. While this is certainly not the first chase in literature it may be the first chase using for that time modern high-speed transportation.
In this second out of four novels about Sherlock Holmes and Watson, Arthur Conan Doyle has Edgar Allan Poe's influence shining through clearly. While in the first Holmes story, Doyle has Holmes complain about Dupin's showy and superficial use of deduction by stating: "That trick of his of breaking in on his friends' thoughts with an apropos remark after a quarter of an hour's silence is really very showy and superficial." - Holmes is now doing the same thing to Watson in the first chapter titled 'The Science of Deduction' by telling him what he did before coming here purely based on his careful observation and deduction. A similar exercise is conducted with Watson's pocket watch. In a way, Doyle acknowledges that Holmes is just like Dupin. Also, the solution of the locked room situation shows clear traces of Poe's Murders in the Rue Morge.
1st edition 1890 serialized in Lippincott's Monthly Magazine as 'The Sign of the Four', later published as a novel under a slightly changed title 'The Sign of Four'; PDF 89 pages.
word count: 43503 which is equivalent to 174 standard pages of text