It is a curious emotion, this certain homesickness I have in mind. With Americans, it is a national trait, as native to us as the roller-coaster or the jukebox. It is no simple longing for the home town or country of our birth. The emotion is Janus-faced: we are torn between a nostalgia for the familiar and an urge for the foreign and strange. As often as not, we are homesick most for the places we have never known.