Arthur Conan Doyle

A man should keep his little brain attic stocked with all the furniture that he is likely to use, and the rest he can put away in the lumber-room of his library, where he can get it if he wants it.

Violence does, in truth, recoil upon the violent, and the schemer falls into the pit which he digs for another.

The lowest and vilest alleys in London do not present a more dreadful record of sin than does the smiling and beautiful countryside.

It is not so impossible, however, that a man should possess all knowledge which is likely to be useful to him in his work, and this, I have endeavoured in my case to do.

[Sherlock Holmes quoting:] "There is danger for him who taketh the tiger cub, and danger also for whoso snatches a delusion from a woman."

"I am glad of all details," remarked my friend, "whether they seem to you to be relevant or not."

It is quite a three pipe problem, and I beg that you won't speak to me for fifty minutes.

...but none the less you must come round to my view, for otherwise I shall keep on piling fact upon fact on you, until your reason breaks down under them and acknowledges me to be right.

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.

Singularity is almost invariably a clue. The more featureless and commonplace a crime is, the more difficult it is to bring it home.

You see, but you do not observe. The distinction is clear.

You know my method. It is founded upon the observation of trifles.