TEACHING MACHINES HAVE SEVERAL ADVANTAGES--TIME IS SAVED, CORRECT RESPONSE IS REINFORCED IMMEDIATELY, AND STUDENTS ARE NOT PUBLICLY CONFRONTED WITH FAILURE. THERE ARE TWO APPROACHES TO THE PROGRAMED INSTRUCTION INTRINSIC TO THEIR USE--ONE (THE SKINNER METHOD) IS BASED ON FILLING IN BLANK SPACES, THE OTHER (THE CROWDER METHOD) EMPLOYS MULTIPLE-CHOICE QUESTIONS. PROMPTING IS MINIMAL IN THE CROWDER METHOD, AND A CONTINUOUS REVIEW IS PROVIDED BY THE METHOD OF BRANCHING--BACKWARD BRANCHING (WASHBACK TECHNIQUE) FOR SLOWER STUDENTS AND FORWARD BRANCHING (SKIP-TECHNIQUE) FOR BRIGHT STUDENTS. SKINNERIAN PROGRAMS EMPHASIZE SHORT, EASY STEPS BETWEEN ITEMS, SO THAT THE LEARNER CAN PROCEED WITHOUT MAKING ERRORS. THERE IS A LARGE MARKET FOR TEACHING MACHINES, BUT THE TESTING OF PROGRAMS SHOULD BE IMPROVED. SOME QUESTIONS MUST BE ANSWERED--WHAT DISCIPLINES BEST LEND THEMSELVES TO BEING TAUGHT IN PROGRAMED FORM. IS ACTIVE RESPONSE REALLY NECESSARY. THE DEVICES SHOULD BE DESIGNED TO SERVE A DESIRED PROGRAM RATHER THAN DESIGNING A PROGRAM TO SUIT THE CAPABILITY OF A GIVEN DEVICE. THE DOCUMENT ALSO CONTAINS, IN THE APPENDICES, SOURCES OF PROGRAMS AND SELF-INSTRUCTIONAL DEVICES. THIS DOCUMENT IS AVAILABLE FOR $5.95 FROM THE TEACHING RESEARCH AND TECHNOLOGY DIVISION OF ELECTRONIC TEACHING LABORATORIES, 5034 WISCONSIN AVE., N.W., WASHINGTON, D.C. 20036. (JO)