The detective story is a kind of intellectual game. It is more-it is a sporting event. And the author must play fair with the reader. He can no more resort to trickeries and deceptions and still retain his honesty than if he cheated in a bridge game. He must outwit the reader, and hold the reader's interest, through sheer ingenuity. For the writing of detective stories there are very definite laws-unwritten, perhaps, but none the less binding: and...