I said that he was my superior in observation and deduction. If the art of the detective began and ended in reasoning from an armchair, my brother would be the greatest criminal agent that ever lived. But he has no ambition and no energy. He will not even go out of his way to verify his own solutions, and would rather be considered wrong than take the trouble to prove himself right.

Desultory readers are seldom remarkable for the exactness of their learning.

Any truth is better than indefinite doubt.

A client is to me a mere unit, a factor in a problem.

If in 100 years I am only known as the man who invented Sherlock Holmes then I will have considered my life a failure.

When we think how narrow and devious this path of nature is, how dimly we can trace it, for all our lamps of science, and how from the darkness which girds it round great and terrible possibilities loom ever shadowly upwards, it is a bold and a confident man who will put a limit to the strange by-oaths into which the human spirit may wander.

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