THIS PAPER REVIEWS RECENT MAJOR STUDIES CONCERNED WITH CLASSROOM INTERACTION WHICH ENCOMPASSES BOTH THE VERBAL AND NONVERBAL BEHAVIOR OF A TEACHER AND THE PUPILS IN ELEMENTARY AND SECONDARY CLASSROOMS. REVIEW OF THE THEORIES UPON WHICH THESE STUDIES WERE BASED WAS NOT WITHIN THE SCOPE OF THIS STUDY. PART 1 BRIEFLY DISCUSSES TWO APPROACHES TO THE CONSTRUCTION OF ITEMS FOR AN OBSERVATIONAL SCHEDULE, THE SIGN SYSTEM AND THE CATEGORY SYSTEM, AND REVIEWS FOUR INSTRUMENTS OF THE OBJECTIVE CATEGORIZATION TYPE. THESE INSTRUMENTS ARE THOSE BY BALES, WITHALL, MEDLEY AND MITZEL, AND FLANDERS.PART 2 DISCUSSES THE FINDINGS REPORTED FROM REPRESENTATIVE STUDIES OF CLASSROOM INTERACTION CONCERNED WITH THREE MAIN AREAS--ELEMENTARY-SECONDARY, INTRAELEMENTARY, AND TEACHER-PUPIL. PART 3 DISCUSSES THE HISTORY OF THE DEVELOPMENT OF THREE ELEMENTS OF CLASSROOM INTERACTION RESEARCH--MEASUREMENT, CRITERIA, AND DATA COLLECTION. THE FIRST OF TWO APPENDIXES PRESENTS TWO PREVIOUSLY UNPUBLISHED RESEARCH PAPERS. ONE PAPER DEALS WITH "VERBAL BEHAVIOR AND SOCIAL STATUS," AND THE OTHER DEALS WITH "STUDENT TEACHERS AND INTERACTION ANALYSES." THE SECOND APPENDIX PRESENTS THE "FAIR" CATEGORIES WHICH ARE ADAPTED FROM THE FLANDERS INTERACTION SCALE. (AL)