"Only when I wander, usually by accident, into my spam box", writes Adam Gopnik, "do I find anything resembling actual affection - prose that captures the spark of human sympathy, the language of exquisite deference, that the Enlightenment philosophers insisted was the necessary mucilage of human societies".

The excessive courtesy of spam letters is, of course, designed to entrap the reader but why, Adam wonders, have the decencies of human correspondence disappeared from virtually all other forms of communication these days.

Producer: Adele Armstrong