In the image and function of a door knocker, 'Knock Before You Enter' discusses the forms of discipline that we encounter in domesticity. 

Knocking on a door and waiting to hear an answer before entering is a form of discipline in America. In Korea, knocking is a slight warning before entering; waiting for a response is not involved. Disciplinary action is taken by striking the hand. The door knocker becomes a protector of the home and mind, which we consider a temple.