As a rule, said Holmes, the more bizarre a thing is the less mysterious it proves to be. It is your commonplace, featureless crimes which are really puzzling, just as a commonplace face is the most difficult to identify.

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.

The best way of successfully acting a part is to be it.

I don't speak for others and they don't speak for me.

A study of family portraits is enough to convert a man to the theory of reincarnation.

Love has been taken away from the poets, and has been brought within the domain of true science. It may prove to be one of the great cosmic elementary forces. When the atom of hydrogen draws the atom of chlorine towards it to form the perfected molecule of hydrochloric acid, the force which it exerts may be intrinsically similar to that which draws me to you. Attraction and repulsion appear to be the primary forces. This is attraction.

To underestimate oneself is as much an exaggeration of one's powers than the other.