This study attempted to provide an analytic basis for an operational definition of open education. The basic aims were 1) to define some of the essential pedagogical features of open education; 2) to develop explicit, concrete indicators for each feature; 3) to check the validity of the indicators with the major writings on the subject and with important theorists and practitioners in the United States and Great Britain; and 4) to make comparisons to other relevant approaches, such as progressive and affective education. Eight major themes were used as a framework: 1) instruction--guidance and extension of learning; 2) provisioning the classroom for learning; 3) diagnosis of learning events; 4) reflective evaluation of diagnostic information; 5) humaneness--respect, openness and warmth; 6) seeking opportunities to promote growth; 7) self-perception--the teacher's view of herself and her role; and 8) assumptions--ideas about children and the process of learning. Specific works of 28 selected authors were examined and analyzed for their attention to each of the eight themes. The authors were classified as writers of historical importance, progressive educators, popular critics, affective educators, and writers on open education. A list of pedagogical characteristics is presented, each accompanied by illustrative quotations from the literature. (MBM)