"The Sign of the Four" is Sir Arthur Conan Doyle's follow-up novel to his immensely successful "A Study in Scarlet", where we first meet two of the most famous literary detectives of all time, Sherlock Holmes and Dr. Watson. "The Sign of the Four", first published in 1890, introduces the reader to Miss Mary Morstan, Dr. Watson's future wife, and centers around the mysterious disappearance of Mary's father, Captain Morstan. Set in 1888, Mary's father has been missing for the past ten years and since 1882, after answering a newspaper ad looking for her, Mary receives an anonymous gift of priceless pearls on the anniversary of his disappearance. Mary solicits the help of Sherlock Holmes and Dr. Watson to unravel the mystery of her father's disappearance and the identity of her anonymous benefactor. Holmes and Watson are soon deep into a dangerous and complex case involving a stolen treasure, the Indian Rebellion of 1857, and a secret pact between four convicts. "The Sign of the Four" is not only a brilliant and engrossing mystery, but it is also the first glimpse of the legendary detective as a complicated human and flawed hero. This edition includes a biographical afterword.