Hildegard E. Peplau (September 1, 1909 - March 17, 1999)[1] was an American nurse and the first published nursing theorist since Florence Nightingale and created the middle-range nursing theory of interpersonal relations, which helped to revolutionize the scholarly work of nurses. As a primary contributor to mental health law reform, she led the way towards humane treatment of patients with behavior and personality disorders.[2][3]