The Adventure of the Final Problem (Unabridged‪)‬

The Adventure of the Final Problem was first published in the Strand Magazine in December 1893. It appears in book form as part of the collection, The Memoirs of Sherlock Holmes. Conan Doyle later ranked The Adventure of the Final Problem fourth on his personal list of the 12 best Holmes stories. 

This story introduces Holmes' greatest opponent, the criminal mastermind Professor Moriarty. Doyle intended this to be his final Holmes story but its ending caused an uproar throughout England and forced him to change his mind.