In the story "Valley of Fear" Holmes asks Watson the following:
"You have heard me speak of Professor Moriarty?"
"The famous scientific criminal, as famous among crooks as --"
In "The Final Problem" Holmes asks Watson:
"You have probably never heard of Professor Moriarty?" said he.
Watson Replies "Never."
Anybody see the error here?
Editor's Note: I see the error; it's two different books.