By the 1980s, it became clear that the systematic study of human care and caring as a distinct feature of the profession of nursing had evolved globally. Dunlop (1986), from Australia, asked: "Is a science of caring possible?" Bjrn (1987) described the caring sciences in Denmark, and Eriksson (1987, 1992) began to develop her theories of caring as communion, and caring as health. Kleppe (1987) discussed the background and development of caring research in Norway. Flynn (1988) compared the caring communities of nursing in England and the United States. Halldorsdottir (1989, 1991), from Iceland, developed research on caring and uncaring encounters in nursing practice and in nursing education. The early endeavors of the first nurse researchers who focused on caring laid out the lines and clarified the observable realities for subsequent research and theorizing. The production of nursing theory is dependent on an intellectual apprehension of the movement between the concrete realities of nursing practice and the abstract world of those assumptions and propositions known as theories (Benoliel, 1977, p. 110). The creation of new knowledge rests on some known assumptions, and Boykin and Schoenhofer's theory builds on the work of three other nurse scholars who have developed theories of caring in nursing, each with a differing apprehension of the realities of human care and caring: Madeline Leininger from an anthropological perspective--one of the first nurse theorists to focus on caring as the essence of nursing practice; Sister M. Simone Roach, who provides a philosophical and theological perspective; and Jean Watson from an existential, philosophical perspective. The significance of Leininger's Culture-Care Theory (1993) is in the study of human care from a transcultural nursing perspective. This focus has led to new and unique insights about care and the nature of caring and nursing in different cultures, and has developed the knowledge so essential to providing culturally sensitive nursing care throughout the world. Roach's work, The Human Act of Caring (1984, 1992) is recognized as one of the most substantive, insightful, and sensitive publications on human caring. Her ultimate conclusion after years of study and reflection is: "Caring is the human mode of being." Watson, in her theory of human care (1985, 1989), addressed the issue of nursing as a humanistic science rather than a formal or biological science. This perspective was an essential paradigm shift for nursing knowledge, but essential for study of the caring phenomena. Within this context, Watson developed a theory of caring in nursing that involves values, a will and a commitment to care, knowledge, caring actions, and consequences. Caring then becomes a moral imperative for practitioners of the profession of nursing.