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The themes of Arthur Conan Doyle's classic work of detective fiction The Sign of the Four include deception, colonialism, and forensics.

Deception is an element common in many works of detective fiction. The Sign of the Four is no exception. The man who started it all is Johnathan Small, who, when attacked by Indian rebels, agreed to help them steal the treasure belonging to the rajah. Small agreed under distress, explaining that he would not have assented had he not been living in the tumultuous times and circumstances of the Indian rebellion. This sets in motion Major John Sholto's subsequent deception of Small himself when Small is in penal colony on the Andaman Islands. Here, Sholto (along with Mary's father) is a guard. The fact that Small was a guard in India when approached by the Arabs concerning the so-called Agra treasure, and, later, Major Sholto is a guard on the penal colony, suggests that the promise of wealth is likely to corrupt the very people in charge of security.

There are many representations of people from India. Though Conan Doyle is relatively progressive writer, he represents non-Westerners in a subordinated way. Mary Morstan's father was an officer in the Indian regiment. In 1857, India attempted to earn independence in an effort which was put down by Britain (who would rule the region until 1947). This begins Mary Morstan's—and by extension, Holmes's—exposure to the subcontinent. Thaddeus Solto has an Indian servant who calls his master (Solto) "Sahib." Conan Doyle describes him as "clad in a yellow turban, white loose-fitting clothes, and a yellow sash. There was something strangely incongruous in this Oriental figure framed in the commonplace door-way of a third-rate suburban dwelling-house" (45). Conan Doyle explicitly avows here that "Hindoos" are unsophisticated, and so out of place in Western (British) environments.

Later, when Holmes enlists the help of the "Baker Street Irregulars," the foreign boys are described as "dirty and ragged little street-Arabs" (153). Finally, the fact that Tonga is responsible for the murder of Bartholomew Solto allows a foreigner to take the fall that would otherwise be on the hands of an Englishman (Small).

Lastly, forensics play an important role in Conan Doyle's work, specifically handwriting analysis and fingerprinting. For example, Mary Morstan herself matches the handwriting on the letter she received instructing her to meet at the Lyceum to the handwriting on the address of the pearls she has been sent in the past. Holmes uses Tonga's footprint to identify him as an accomplice in the murder of Bartholomew Sholto.


One theme of The Sign of the Four is the attempt to right injustice. Mary Morstan comes to Sherlock Holmes with a letter that says she has been treated unjustly and which calls her a "wronged woman." As Thaddeus Sholto later explains, his father, Major John Sholto, has kept Mary's father's death a secret from her for ten years and "withheld from her the treasure" she was supposed to have. Thaddeus wants to give Mary her part of the treasure, but then it is stolen. The pure Mary is the wronged innocent whose rights Sherlock Holmes hopes to defend by discovering the whereabouts of the fortune.

Another theme is the...

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