It is necessary to develop a theoretical model to define the concept and practices in the field of educational technology. In the 1950s and '60s, developments in communications theory and systems concepts led to studies of the educational process, its elements, and their interrelations. As a result of these studies, the field of audiovisuals shifted its emphasis from devices and materials to the examination of the teaching-learning process. The field was now known as audio-visual communications and educational technology. As the technology improves, educational capabilities increase correspondingly. The emergence of inexpensive computer technology and mass storage media, including optical videodisks and compact disks, has given instructional technologists better tools with which to work. The modern learning stations combine the advantages of reference materials, still pictures, motion pictures, television, and computer-aided instruction. With even newer technologies now being developed, such learning stations will eventually be commonplace in homes for both entertainment and educational purposes. Information Technology (IT) is capable of becoming a major resource for the delivery of educational services. The principal benefits will be realised from combinations of new technologies rather than from any single device. The present work, in three volumes, encompasses valuable readings focused on all aspects of modern educational technology