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

My mind rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram, or the most intricate analysis, and I am in my own proper atmosphere. But I abhor the dull routine of existence. I crave for mental exaltation.

It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts.

[Sherlock Holmes:] The temptation to form premature theories upon insufficient data is the bane of our profession.

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

What the deuce is it to me?" he interrupted impatiently: "you say that we go round the sun. If we went round the moon it would not make a pennyworth of difference to me or to my work.

Life, my dear Watson, is infinitely stranger than fiction; stranger than anything which the mind of man could invent. We could not conceive the things that are merely commonplace to existence. If we could hover over this great city, remove the roofs, and peep in at the things going on, it would make all fiction, with its conventionalities and foreseen conclusions flat, stale and unprofitable.