I cannot live without brainwork. What else is there to live for

No man lives or has ever lived who has brought the same amount of study and of natural talent to the detection of crime which I have done.

Man, or at least criminal man, has lost all enterprise and originality. As to my own little practice, it seems to be degenerating into an agency for recovering lost lead pencils and giving advice to young ladies from boarding-schools.

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.

Crime is common. Logic is rare. Therefore it is upon the logic rather than upon the crime that you should dwell.

We had got as far as this, when who should walk in but the gentleman himself, who had been drinking his beer in the taproom and had heard the whole conversation. Who was I? What did I want? What did I mean by asking questions? He had a fine flow of language, and his adjectives were very vigorous.

There is no satisfaction in vengeance unless the offender has time to realize who it is that strikes him, and why retribution has come upon him.