A classic Holmes novel, The Sign of the Four is perhaps one of Sherlock's most puzzling mysteries. As told by Dr. Watson, this mystery may have been one of Holmes's toughest cases yet. As Sherlock is injecting cocaine into his blood system, he sits down with placid relief, until there is a knock at the door. In enters the beautiful Mary Morstan, whom Watson immediately takes a fancy to. While Watson observes her beauty, Holmes observes her problem. It seems that she is a rather middle-class woman, with style and father in the military, who is currently stationed in India. He had recently wrote to her saying that he would come to visit. However, he never showed up when she went to pick him up. That was ten years ago. But starting six years ago, four years after his disappearance, Miss Morstan had been receiving mysterious packages containing pearls of great value, one a year. Having been contacted by her mysterious complimentor, should she go and meet him? Or should she stay home? The truth lies with in the book. This book is a triumph for the Doyle, as well as a great read for those who are fond of mystery novels and thrillers.