The Sign of the Four is a detective novel written by Arthur Conan Doyle and published in 1890. It is the second novel featuring the famous detective Sherlock Holmes and his loyal friend and assistant, Dr. John Watson. The story begins with a young woman named Mary Morstan who seeks the help of Holmes and Watson to solve the mystery of her missing father, who disappeared ten years ago. Along with the disappearance, Mary has also received an anonymous gift of a valuable pearl each year for the past six years, and now she has received a letter asking her to meet the sender. Holmes and Watson agree to take on the case and soon find themselves embroiled in a complex web of intrigue involving stolen treasure, betrayal, and murder. They follow a trail of clues that takes them from London to a remote island in the Andaman Sea, where they finally uncover the truth behind the mystery of Mary's missing father and the strange gifts she has been receiving. The Sign of the Four is a thrilling and suspenseful mystery that showcases the brilliant deductive skills of Sherlock Holmes and the steadfast loyalty of Dr. Watson. It is also notable for introducing the character of Mary Morstan, who would later become Watson's wife in Doyle's later works.Sherlock Holmes took his bottle from the corner of the mantel- piece, and his hypodermic syringe from its neat morocco case. With his long, white, nervous fingers he adjusted the delicate needle and rolled back his left shirtcuff. For some little time his eyes rested thoughtfully upon the sinewy forearm and wrist, all dotted and scarred with innumerable puncture-marks.This scarce antiquarian book is a facsimile reprint of the old original and may contain some imperfections such as library marks and notations. Because we believe this work is culturally important, we have made it available as part of our commitment for protecting, preserving, and promoting the world's literature in affordable, high quality, modern editions, that are true to their original work.