This chapter is based on three papers, respectively entitled: "The Erotic Transference and Boundaries", "The Negative Transference", and "Countertransference". Interpreting the transference is the single factor that most clearly differentiates psychotherapy that has been derived from psychoanalysis from other therapies. It was the interpretation of the erotic transference that changed Freud from being a hypnotist and using a therapy associated with hypnosis to being a psychoanalyst. Freud came to realize that the hypnotic trance came about through the presence of an erotic factor. The word "sexual" is used as it would be used by the man in the street—that is, feelings that are aroused in the genital area in the presence of a stimulating object, most obviously by a member of the opposite sex, but sometimes by someone of the same sex. The crucial factor that enables the patient to let go of the erotic transference is through the psychotherapist holding the treatment boundaries as firmly as possible.