Strong mood swings, fear of abandonment, and a disturbed self-perception make borderline disorder a challenging issue for those affected and their loved ones. What inner motives give rise to these symptoms? What consequences arise for interpersonal encounters? What feelings do borderline patients evoke in their interaction partners? Starting from medical nosology and moving through psychodynamic-psychoanalytic diagnostics, Johann Steinberger connects to the core of his book: the inner psychological experiences of those affected, which he analyzes using letters, conversation protocols, and conversation analysis. The focus of his qualitative data analysis is on the inner psychological involvement that can lead to corresponding reactions in encounters or guide them.