'It is my duty to warn you that it will be used against you,' cried the Inspector, with the magnificent fair play of the British criminal law.

He [Professor Moriarty] is the Napoleon of crime, Watson. He is the organizer of half that is evil and of nearly all that is undetected in this great city. He is a genius, a philosopher, an abstract thinker. He has a brain of the first order.

It has always seemed to me that so long as you produce your dramatic effect, accuracy of detail matters little. I have never striven for it and I have made some bad mistakes in consequence. What matter if I hold my readers?

Sir Walter, with his 61 years of life, although he never wrote a novel until he was over 40, had, fortunately for the world, a longer working career than most of his brethren.

"Dr. Munro, sir," said he, "I am a walking museum. You could fit what ISN'T the matter with me on to the back of a -- visiting card. If there's any complaint you want to make a special study of, just you come to me, sir, and see what I can do for you. It's not every one that can say that he has had cholera three times, and cured himself by living on red pepper and brandy."

There is nothing more stimulating than a case where everything goes against you.

They say that genius is an infinite capacity for taking pains," he remarked with a smile. "It's a very bad definition, but it does apply to detective work.