Sherlock Holmes: A Scandal in Bohemia

This book reminds me a little of “The Purloined Letter” by Edgar Allan Poe. But Conan Doyle focuses on the same problem in a different way and that makes the story unique. Besides the character of Irene Adler is (apart from Professor Moriarty) equals the only intelligence to Sherlock Holmes. It's a great story set in Victorian London.