The most difficult crime to track is the one which is purposeless.

Depend upon it, there is nothing so unnatural as the commonplace.

We can't command our love, but we can our actions.

When the impossible has been eliminated, all that remains no matter how improbable is possible.

It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.

I am afraid that I rather give myself away when I explain," said he. "Results without causes are much more impressive.

Ex-Professor Moriarty of mathematical celebrity... is the Napoleon of crime, Watson.