In this article, we illuminate the affective phenomenon of loneliness by exploring the question of how it relates to love and other forms of friendship. We reflect in particular on the question of how different forms of loneliness are relevant to human existence. Distinguishing three forms of loneliness, we first introduce two border cases of loneliness: unfelt loneliness in which one’s individuality is denied and one therefore cannot feel lonely; and existential loneliness in which the possibility of intimacy and existential (...) communication are denied and one therefore cannot but feel lonely. We then turn to loneliness that occurs within intimate friendships—even the most intimate ones. In our analysis, we pay attention especially to the role of communication. In order to do so, we repeatedly turn to poetic expressions of loneliness. We argue that loneliness cannot reflect only the absence or partial failure of communication but also the inherent limits of communication. These limits in turn point back to the nature of human existence and love itself. (shrink)