This part introduction presents an overview of the key concepts discussed in the subsequent chapters. The part suggests that the setting of the couple psychotherapy, which includes the therapist(s), offers the couple a “breathing space” within which reflection and self-realization may be possible. It shows that internal images stemming from each partner’s experiences of their parents’ marriages and their relationship to the parental marriage will influence the way in which the partners make use of both each other in their intimate relationship, and the psychotherapist(s) in the course of the couple psychotherapy. The part provides an overview of some of the central themes in the theory and practice of psychotherapy with couples. It outlines object relations theory, particularly as it has been influenced by some of the concepts introduced by M. Klein and her colleagues, and also shows how it is a particularly appropriate construct with which to think about the intimate couple relationship.