My sister and I, you will recollect, were twins, and you know how subtle are the links which bind two souls which are so closely allied.

My dear Watson," said [Sherlock Holmes], "I cannot agree with those who rank modesty among the virtues. To the logician all things should be seen exactly as they are, and to underestimate one's self is as much a departure from truth as to exaggerate one's own powers.

It is decreed by a merciful Nature that the human brain cannot think of two things simultaneously . . .

Anything seems commonplace, once explained.

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.

Of all ruins, that of a noble mind is the most deplorable.

Accounts are not quite settled between us," said she, with a passion that equaled my own. "I can love, and I can hate. You had your choice. You chose to spurn the first; now you must test the other.