It is not that I think or believe, but that I know.

...Holmes, who loathed every form of society with his whole Bohemian soul, remained in our lodgings in Baker Street, buried among his old books, and alternating from week to week between cocaine and ambition, the drowsiness of the drug, and the fierce energy of his own keen nature.

...it was a huge creature, luminous, ghastly, and spectral. I have cross-examined these men, one of them a hard-headed countryman, one a farrier, and one a moorland farmer, who all tell the same story of this dreadful apparition, exactly corresponding to the hell-hound of the legend. I assure you that there is a reign of terror in the district, and that it is a hardy man who will cross the moor at night.

Do you know, Watson," said he, "that it is one of the curses of a mind with a turn like mine that I must look at everything with reference to my own special subject. You look at these scattered houses, and you are impressed by their beauty. I look at them, and the only thought which comes to me is a feeling of their isolation and of the impunity with which crime may be committed there.

The love of books is among the choicest gifts of the gods.

I have heard, Mr. Holmes, that you can see deeply into the manifold wickedness of the human heart.

"I have seen those symptoms before," said Holmes, throwing his cigarette into the fire. "Oscillation upon the pavement always means an affaire de coeur."