This document discusses Hildegard Peplau's theory of interpersonal relations in nursing. It outlines Peplau's concepts of person, environment, and health. It also describes the six nursing roles in Peplau's theory - stranger, resource, teacher, counselor, surrogate, and leader. Finally, it summarizes Peplau's four developmental stages of the nurse-client relationship: orientation, identification, working, and resolution/termination.