“Circumstantial evidence is a very tricky thing. It may seem to point very straight to one thing, but if you shift your own point of view a little, you may find it pointing in an equally uncompromising manner to something entirely different”

“When once your point of view is changed, the very thing which was so damning becomes a clue to the truth.”

“It is a great thing to start life with a small number of really good books which are your very own.”

“It is not really difficult to construct a series of inferences, each dependent upon its predecessor and each simple in itself. If, after doing so, one simply knocks out all the central inferences and presents one's audience with the starting-point and the conclusion, one may produce a startling, though perhaps a meretricious, effect.”

“When a man does a queer thing, or two queer things, there may be a meaning to it, but when everything he does is queer, then you begin to wonder”

“Really, Watson, you excel yourself," said Holmes, pushing back his chair and lighting a cigarette. "I am bound to say that in all the accounts which you have been so good as to give of my own small achievements you have habitually underrated your own abilities. It may be that you are not yourself luminous, but you are a conductor of light. Some people without possessing genius have a remarkable power of stimulating it. I confess, my dear fellow, that I am very much in your debt.”

“The most serious point in the case is the disposition of the child."What on earth has that to do with it?" I ejaculated.My dear Watson, you as a medical man are continually gaining insight as to the tendencies of a child by the study of the parents. Don't you see that the converse is equally valid. I have frequently gained my first real insight into the character of parents by studying their children.”