B.F. Skinner applied his concept of operant conditioning to education. Skinner believed that people acted the way they did because they had been reinforced for behaving in a certain manner. His orientation to pedagogy was predicated upon the notion that a student's behavior could be modified by guiding the student through the learning process using carefully arranged reinforcements. Operant conditioning was the cornerstone of Skinnerian programmed instruction. Skinnerian programmed instruction broke subject matter down into small steps (frames), allowed for self-pacing, and provided immediate feedback. Skinner promoted the use of teaching machines and programmed textbooks. Teaching machines were used to control the presentation of frames, keep records of students' answers, and evaluate, score, and reinforce correct behavior immediately either by controlling and advancing the next frame or by displaying the correct answer. Programmed textbooks presented machine teaching-type learning sequences without hardware. The paper discusses implementation and effectiveness of teaching machines and programmed instruction during the 1950s-60s, noting teachers' and students' mixed responses and describing the eventual demise of this type of teaching. (Contains 58 endnotes.) (SM)