The unique detective, Sherlock Holmes. His methods of deduction are what make the novel special. He can observe the smallest details and draw amazing conclusions.
The writing style of 'A Study in Scarlet' is special. It combines vivid descriptions of the settings, whether it's the dingy streets of London or the wild landscapes of Utah. The dialogue is sharp and helps to move the mystery forward. It was one of the first novels to introduce such a methodical and intelligent detective, which set a new standard for mystery novels. It also has a certain atmosphere of mystery and suspense that is maintained from the very first page to the last.
The plot is really well - constructed. It starts with a mysterious murder and then gradually unfolds the backstory through different timelines. The contrast between the modern London setting and the past events in Utah adds to the mystery. Also, the characters are well - developed. Holmes and Watson's relationship is a key part. Watson's narration gives the reader a perspective of someone in awe of Holmes' abilities. And the motives behind the crime are complex and not easily guessed at the beginning, which keeps the reader engaged throughout the novel.