For a long time, John Bowlby's attachment theory was given little consideration in psychotherapy, despite being conceived as a clinical theory. It was only through theoretical advancements and new findings from clinical attachment research, such as the relationship between attachment experiences and psychopathology, that the concept gained increasing importance in psychoanalysis. This book summarizes the theoretical foundations and essential insights of attachment research and makes them accessible for psychotherapeutic practitioners. Through numerous examples, Strauss illustrates the connection of the attachment concept to important aspects of psychotherapy, such as the quality of the therapeutic relationship, thereby highlighting its significance for therapeutic practice.