Playing Fair With the Detective Story Reader

The most frequently repeated rule of detective fiction is the most nonsensical. It says, "you must play fair with the reader," meaning that in the course of the narrative the reader must see and hear everything that the detective sees and hears. I don't know why mystery writers have insisted on it, since every good writer of detective stories has violated this rule over and over again. [And they do so at the expense of the reader.]

Rex Stout in The Writer's Book, edited by Helen Hull, 1959