The Final Problem: A Sherlock Holmes Adventure (Unabridged) [Unabridged Fiction‪]‬

This is the story, set in 1891, that introduces Holmes' greatest opponent, the criminal mastermind Professor Moriarty.

As is well known, "The Final Problem" was intended to be exactly what its name says. Conan Doyle meant to stop writing about his famous detective with this short story - equally well-known, this device failed in its purpose; only the few free surviving members of Moriarty's organization and Holmes' brother Mycroft know that Sherlock Holmes is still alive.