This two-volume report summarizes and comments on international research into distance education done after 1970 and on some older research deemed still to be important. In the first volume, the review of research and development work is organized into 15 topic areas: (1) general analyses of distance education, philosophy and theory; (2) studies of student groups and students' motivation; (3) course planning and study objectives; (4) course development; (5) media; (6) non-contiguous tutorial two-way communication; (7) face-to-face sessions; (8) counselling; (9) institutional planning, organization and administration; (10) economics of distance education; (11) evaluation; (12) history of distance education; (13) distance education in developing countries; (14) guidelines for distance educators; and (15) research on research. An appendix provides summaries of research projects too special or too technical to have been included in the main presentation, and 22 references are listed. The second volume is a supplement which covers 10 of the same research areas (omitting those numbered 1, 10, 11, 12, and 14 above) and includes 12 pages of additional references. (LMM)