D.Ed. (Media Science) / The use of educational media in education and training is a reality. In order to use media optimally two possible sources of information and expertise come to mind, namely own cumulative experience and research. Experience can often be very shallow and unsatisfactory and could necessitate augmentation by the findings of research and a fuller grasp of the extent of the theoretical base within a particular field of study. As there are persistent indications that the theoretical bases of educational technology and media science leave much to be desired and that media research does not fulfil expectations, it was deemed prudent to investigate theory formation and explication in the field of media science (a subset of educational technology). The following aims were pursued: * Further theory formation regarding the nature and focus of educational technology and media science and the placement of both fields of study within the discipline of education. * The development of a model for media research. * The development of criteria or the redirection of existing criteria for the assessment of media research. * A discussion of the implications of the above for media utilization. In order to realize these aims, theory formation in the discipline of education was investigated and an overview of educational research (as one form of manifestation of theory formation) undertaken. As media science forms part of educational technology, tho developments in both fields were reviewed. Media research forms a substantial mechanism whereby theory formation can take place, therefore the media research (past and present) is dealt with extensively. Each of these themes are dealt with in terms of its history, current status and future prospects...