Mentalization as a term in psychiatry was firstly introduced by Peter Fonagy in 1991. Based primarily on cognitive science, mentalization has its roots in other fields of science and psychoanalysis. Mentalizing is important for mental health for a number of reasons. We recognize mentalization as a person's ability to understand own actions and actions of other people as well as himself in the form of thoughts, feelings, desires and needs. It enables (self)control and a healthy perception of oneself, and it gives a person a sense of continuity. In addition to mentalization, other phenomena and concepts similar to it are briefly explained in this work: theory of mind, symbol formation or symbolization), mindfulness, psychological mindedness, empathy, affect consciousness, emotional intelligence, intersubjectivity, introspection, reflective function and metacognition. Operationalization and measurement of mentalization are important aspects of research that enable the evaluation and objective assessment of this function. This is done with different instruments and questionnaires that measure different areas and/or dimensions of mentalizing ability. The paper describes the use of MBT as a form of therapy for various disorders such as psychosis, eating disorders, addictions, depression, PTSD and trauma, and borderline personality disorder. At their core, they have problems related to mentalization and it is precisely in this field that they show stagnation. The establishment of adequate mentalization where it is insufficient or does not exist at all, is the fundamental path to healing. As a "young" researched area of psychoanalysis and neuroscience in general, mentalization certainly offers various possibilities and advantages in clinical medicine of the 21. st. century.