“He was, I take it, the most perfect reasoning and observing machine that the world has seen, but as a lover he would have placed himself in a false position. He never spoke of the softer passions, save with a gibe and a sneer. They were admirable things for the observer- excellent for drawing the veil from men's motives and actions. But for the trained observer to admit such intrusions into his own delicate and finely adjusted temperament was to introduce a distracting factor which might throw a doubt upon all his mental results. Grit in a sensitive instrument, or a crack in one of his own high-power lenses, would not be more disturbing than a strong emotion in a nature such as his.”

“They were admirable things for the observer - excellent for drawing the veil from men's motives and actions. But for the trained reasoner to admit such intrusions into his own delicate and finely adjusted temperament was to introduce a distracting factor which might throw a doubt upon all his mental results. Grit in a sensitive instrument, or a crack in one of his own high-power lenses, would not be more disturbing than a strong emotion in a nature such as his.”

“Leto turned a hard stare at Kynes. And Kynes, returning the stare, found himself troubled by a fact he had observed here: This Duke was concerned more over the men than he was over the spice. He risked his own life, and that of his son to save the men. He passed off the loss of a spice crawler with a gesture. The threat to men's lives had him in a rage. A leader such as that would command fanatic loyalty. He would be difficult to defeat.Against his own will and all previous judgements, Kynes admitted to himself: I like this Duke.”

“To Sherlock Holmes she is always the woman. I have seldom heard him mention her under any other name. In his eyes she eclipses and predominates the whole of her sex. It was not that he felt any emotion akin to love for Irene Adler. All emotions, and that one particularly, were abhorrent to his cold, precise but admirably balanced mind. He was, I take it, the most perfect reasoning and observing machine that the world has seen.... And yet there was but one woman to him, and that woman was the late Irene Adler, of dubious and questionable memory.”

“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.”

“I will say only that all a writer has to work with is the material he has gathered as the result of his own endeavor and observations, and he cannot be denied the right to use it. Condemn, but not deny.”