Interest in audiovisual aids in education has been increased by the shortage of classrooms and good teachers and by the modern predisposition toward learning by visual concepts. Effective utilization of audiovisual materials and equipment depends most importantly, on adequate preparation of the teacher in operating equipment and in coordinating audiovisual experiences with general teaching objectives. Nor can this be left to chance, but must be planned for in teacher-training. Basic to the case of audio equipment of all types is an understanding of the functions of the "pickup," the amplifier, and the loudspeaker parts of the equipment. Essential ingredients of visual aid equipment are lenses, light sources (generally projection lamps), and screens. In addition to the traditional types of audiovisual aids--slide and motion-picture projectors, phonographs and tape recorders--programed teaching machines have been successful where the teacher has understood the program and integrated it with other aids. Television and radio are also applicable in the classroom. While mastery over equipment is basic, so is the use of appropriate materials, many of which (e.g., diazo transparencies) can be produced in the classroom. Descriptions and operating instructions are given for each type of equipment. (JS)