Conan Doyle was well read in the field of mysteries and drew on many sources for his own well-wrought stories. The most important precedents for the Holmes adventures were the tales of "ratiocination" of Edgar Allan Poe and the novels of Wilkie Collins. Poe's tales feature the great detective Auguste Dupin, a Frenchman who uses his intellect to solve bewildering crimes. As in the Holmes stories, someone brings Dupin a mystery; then Dupin sifts through the clues and devises a plan to unmask the villain.

Conan Doyle's stories follow this pattern, even making Holmes analytical and arrogant like Dupin.

In his two best novels, The Woman in White (1859) and The Moonstone (1868), Collins tells the stories through the letters and diaries of the characters.

This technique creates a tone of immediacy, as if the reader were seeing the narrative unfold moment by moment.

In addition, the mystery...