"I must apologize for calling so late," said he, "and I must further beg you to be so unconventional as to allow me to leave your house presently by … - Arthur Conan Doyle

for nothing clears up a case so much as stating it to another person,

He is the Napoleon of crime, Watson. He is the organizer of half that is evil and of nearly all that is undetected in this great city, He is a genius, a philosopher, an abstract thinker. He has a brain of the first order. He sits motionless, like a spider in the center of its web, but that web has a thousand radiations, and he knows well every quiver of each of them. He does little himself. He only plans.

How terrible is wisdom when it brings no profit to the wise.