All Visitors Must Be Announced: The Lives and Loves of Doormen in New York City (1997)

One chooses to have a doorman mainly for practical reasons and safety. The friendly smile every time you arrive at or leave your building is a pleasant extra that makes the sometimes lonely life in this big city somewhat more bearable. The presence of the doorman appears to be hardly noticed. In most cases however he knows more about his residents than they would like to believe.