This report describes the development of an economically viable teaching system using a computer-based educational system. The PLATO system, used at the University of Illinois for the past nine years, is discussed. The authors report that by using newly-developed technological devices it is economically and technically feasible to develop large-scale computer-controlled teaching systems for handling 4000 teaching stations. The cost of instruction would be comparable to the cost of teaching in elementary schools. (Author/FL)