A study in scarlet, eh? Why shouldn't we use a little art jargon? There's the scarlet thread of murder running through the colourless skein of life, and our duty is to unravel it, and isolate it, and expose every inch of it.

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

On glancing over my notes of the seventy odd cases in which I have during the last eight years studied the methods of my friend Sherlock Holmes, I find many tragic, some comic, a large number merely strange, but none commonplace; for, working as he did rather for the love of his art than for the acquirement of wealth, he refused to associate himself with any investigation which did not tend towards the unusual, and even the fantastic.

The unexpected has happened so continually in my life that it has ceased to deserve the name.

A dog reflects the family life. Whoever saw a frisky dog in a gloomy family, or a sad dog in a happy one? Snarling people have snarling dogs, dangerous people have dangerous ones.

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

There's a light in a woman's eyes that speaks louder than words.