Narcissistic personality disorder has become increasingly more prevalent in today's society; especially if we do not only take into account the full-blown personality disorder itself, but also just certain narcissistic personality traits such as constant need for admiration and confirmation from others. Borderline personality disorder describes an emotionally unstable personality with truly unpredictable mood swings. The aim of this thesis is to provide a basic overview of the narcissistic and borderline personality disorders, particularly through current psychodynamic explanations of their functioning. The cornerstone works in this area have been presented by Otto Friedmann Kerneberg and Joan Lackhar, and are explained in depth. There is also a discussion on the relationship between a borderline and a narcissist and how they complement each other in both, sexual and love relationships. Specific phenomena to be paid attention to in these personality disorders – shame, perfectionism and suicidality and their inter-connectedness are also addressed. This paper additionally touches on motives for criminal and violent activities and what kind of gains people suffering from NPD and BPD obtain. Furthermore, this thesis describes revenge - on personal as well as group and social level, in addition to its possible dissolution and the rocky way out, and how to start the process of forgiveness and reconciliation, and healthy mourning. There is a description of the social aspect of narcissism, nacissism in society and culture, and a question of whether the society itself forces us into perfectionism and narcissism. Therapy for BPD and NPD is still a challenge, however there are some developed therapeutic techniques that have been used to equalize these patients' external and internal realities. One of the newer and more intriguing ones is definitely mentalization , namely Mentalization Based Therapy- MBT which offers some hope in the future of treatment of these personality disorders.