If caring is to be retained as the "essence" of nursing, and if research in this area is to advance, then the various perspectives of caring must be clarified, the strengths and the limitations of these conceptualizations examined, and the applicability of caring as a concept and theory to the practice of nursing identified. Examination of the concept of caring resulted in the identification of five epistemological perspectives: caring as a human state, caring as a moral imperative or ideal, caring as an affect, caring as an interpersonal relationship, and caring as a nursing intervention. Two outcomes of caring were identified: caring as the subjective experience and as the physiologic responses in patients. The authors concluded that knowledge development related to caring in nursing is limited by the lack of refinement of caring theory, the lack of definitions of caring attributes, the neglect to examine caring from the dialectic perspective, and the focus of theorists and researchers on the nurse to the exclusion of the patient.