This paper traces the historical roots of mental health nursing relating these to contemporary practice in the case of people with all forms of mental illness. An attempt is made to explain the current interest in the nurse's interpersonal role with reference to specific theoreticals models and the development of care practices which emphasise social systems or social relationships. Emphasis is given to reports in the British literature, although some reference is made to North American nursing commentators. It is argued that although research evidence is weak, strong indications exist to suggest that the nurse's primary role lies in the imagination of their interpersonal relationship with the patient in an attempt to effect lasting change in the patient's capacity to live an ordinary life.