Although Sherlock Holmes is not the first investigator to appear in fiction—predecessors include Edgar Allan Poe’s Auguste Dupin and Charles Dickens’s Inspector Bucket—he has become the most famous and iconic detective character, spawning the detective and mystery genres. His creator, Sir Arthur Conan Doyle, originally based the character on a doctor he had trained under in medical school; the man’s ability to diagnose complex ailments by making detailed and seemingly irrelevant observations about each patient was inspiring. The popularity of the stories featuring Holmes, while not initially successful, reached such a fever pitch in the early 20th century that Doyle was forced to bring Holmes back from the dead after trying to kill the character off.

As the first of Doyle’s works to feature Sherlock Holmes, A Study in Scarlet establishes a lot of the characteristics that will come to define the character throughout the series: eccentric in his interests and knowledge, arrogant and self-confident, not sociable, cold toward others, and excitable when facing an interesting case. Holmes pretends he does not care what others think about him, but at the same time yearns for recognition and has a flair for the dramatic when investigating. He goes through episodes of working tirelessly, but then spends days barely moving—a cycle that foreshadows the cocaine use future short stories describe.