In a vintage joke about psychiatrists, an analyst scrutinizes a colleague who has just wished him good morning and ponders, "Now what did he mean by that?"
To University of Pennsylvania Sociologist Erving Goffman, that hoary punch line is a legitimate scientific query. In fact, Goffman has been asking —and answering—just such questions for years. He believes that greetings and goodbyes, congratulations and condolences, along with the other little ceremonies of daily life, serve serious purposes: they grease the wheels of social intercourse and help each person to create an acceptable image of himself in the eye of his fellows.
That is the...