In this paper, we develop an analysis of the structure and content of loneliness. We argue that this is an emotion of absence-an affective state in which certain social goods are regarded as out of reach for the subject of experience. By surveying the range of social goods that appear to be missing from the lonely person's perspective, we see what it is that can make this emotional condition so subjectively awful for those who undergo it, including the profound sense (...) of being unable to realise oneself, in collaboration with others. (shrink)