The Sign of the Four presents Sherlock Holmes with a case of treasure, betrayal, and vengeance spanning continents. When Mary Morstan seeks Holmes's help to uncover the truth behind her father's disappearance, the investigation leads to an exotic mystery rooted in colonial India. Fast-paced, richly atmospheric, and filled with intrigue, it remains a fan favorite.

Sir Arthur Conan Doyle (1859–1930) was a Scottish author, physician, and spiritualist best known for creating the legendary detective Sherlock Holmes. Born in Edinburgh, he studied medicine at the University of Edinburgh, where his storytelling talent began to emerge alongside his scientific education. Though initially practicing as a doctor, Doyle turned to writing to support himself, eventually achieving worldwide fame with the publication of A Study in Scarlet in 1887. Beyond detective fiction, he explored historical novels, science fiction, and supernatural themes, notably in the Professor Challenger series. A passionate advocate for justice, he was involved in several real-life legal investigations. In his later years, Doyle became deeply involved in spiritualism, dedicating much of his time and writings to life after death. His legacy endures as one of the most influential figures in literary history.