Teaching machines and programed instruction represent new methods in education, but they are based on teaching principles established before the development of media technology. Today programed learning materials based on the new technology enjoy increasing popularity for several reasons: they apply sound psychological theories; the materials can easily be fitted into existing instructional programs, supplementing or replacing teachers; and almost all subjects can be programed. Unfortunately, there is, at present, a deplorable lack of standardization in technological design, and marketing procedures seem to stress the educational-toy characteristics of the material. Successful instruction requires a thorough knowledge of the application, logistics, and costs of programed materials. The programer has to have a clear concept of the goals of education and of the level of achievement expected of the students; he must master the subject to be taught; and he must be familiar with the characteristics of the students. With these factors in mind he must decide upon a suitable approach for the programed materials and then design the appropriate learning sequences. Equally important considerations are the cost, supply, maintenance, space, and staff problems created by machines. Appendices include a classification of variables in a programed learning situation and examples of programed sequences. (OH)