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

There are heroisms all round us waiting to be done.

All other men are specialists, but his specialism is omniscience.

What you do in this world is a matter of no consequence. The question is, what can you make people believe that you have done?

Before turning to those moral and mental aspects of the matter which present the greatest difficulties, let the inquirer begin by mastering more elementary problems.

Detection is, or ought to be, an exact science, and should be treated in the same cold and unemotional manner.

Some facts should be suppressed, or, at least, a just sense of proportion should be observed in treating them.