The Complete Sherlock Holmes

by Arthur Conan Doyle

Depend upon it there comes a time when for every addition of knowledge you forget something that you knew before. It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones."

Therefore all the knowledge which he possessed was such as would be useful to him.

Like all other arts, the Science of Deduction and Analysis is one which can only be acquired by long and patient study nor is life long enough to allow any mortal to attain the highest possible perfection in it.

I am simply applying to ordinary life a few of those precepts of observation and deduction which I advocated in that article.

You know a conjuror gets no credit when once he has explained his trick, and if I show you too much of my method of working, you will come to the conclusion that I am a very ordinary individual after all."

There is a mystery about this which stimulates the imagination; where there is no imagination there is no horror.

"you should never neglect a chance, however small it may seem."

"To a great mind, nothing is little,"

ought to know by this time that when a fact appears to be opposed to a long train of deductions, it invariably proves to be capable of bearing some other interpretation.

The most commonplace crime is often the most mysterious because it presents no new or special features from which deductions may be drawn.

In solving a problem of this sort, the grand thing is to be able to reason backwards.

In the every-day affairs of life it is more useful to reason forwards, and so the other comes to be neglected.

There are fifty who can reason synthetically for one who can r...