The Sign of Four continues the partnership of Holmes and Watson as they are faced with an even more devious crime. A young governess named Mary Morstan comes to consult Holmes. Her father disappeared, presumed dead, nearly ten years ago. Four years after his death she began to receive strange gifts in the mail: once a year a large, lustrous pearl in an unmarked box. Now she has a received an unsigned letter calling her a wronged woman who deserves justice. Add to this a man killed in a locked room, a missing ancient treasure, a poison dart gun and a high speed boat chase on the Thames. This story has always struck me as one of most bizarre in the Holmes canon, but no less enjoyable for it.

The Scientific Sherlock Holmes is a scholarly fan's discussion of the use of various scientific methods for crime solving in the Sherlock Holmes stories. The book includes chapters on finger prints, foot prints, hand writing analysis, cryptography and tracking dogs, comparing each of these as used by Holmes against their uses in modern criminal cases. I was surprised to learn that many of the techniques discussed (particularly finger prints) were, at the time of Conan Doyle's writing, revolutionary new ideas in police work. Also examined are Holmes' knowledge of chemistry, biology, geology, physics and mathematics. Two sections I particularly enjoyed were a discussion of false gems and brief afterward about famous hoaxes credited to Conan Doyle himself. Google “The Piltdown Man” if you are curious about the later.

The Art of Detection is the fifth book in the Kate Martinelli detective series, but the first one that I've read. In this book Martinelli, a hardworking lesbian detective living in foggy San Francisco, discovers one of the strangest crimes of her career. A man in a Victorian silk dressing gown has been found murdered, his body dumped in the Marin Headlands. When Martinelli enters the victim's house, she finds that the robe was not the only Victorian item that the man owned; his living quarters are a near perfect replica of apartment at 221 B Baker Street, as described by Sir Arthur Conan Doyle. With the famous consulting detective unavailable, it is left to Martinelli to figure out who killed this Sherlock Holmes obsessive and why.