THE MICROWAVE RESPIRATION MONITOR IS SUPERIOR IN MANY RESPECTS TO THE PNEUMOGRAPH IN USING THE STANDARD POLYGRAPH. PHYSICAL AND PSYCHOLOGICAL DISCOMFORT IS AVOIDED, AND THE MONITOR CAN BE REGULATED TO RECEIVE OPTIMAL RECORDING AT ALL TIMES. THE DEVICE CAN BE CALIBRATED, AND RESPIRATION RECORDINGS CAN BE QUANTIFIED. REMOTE SENSING IS EFFECTED BY REFLECTING A MICROWAVE BEAM FROM THE LOWER TORSO OF THE SUBJECT, COMBINING WITH A REFERENCE BEAM, AND SQUARE-LAW DETECTING THE RESULTS. OUTPUT OF THE SQUARE-LAW DETECTOR INCLUDES A SIGNAL THAT IS A SINUSOIDAL FUNCTION OF THE LENGTH OF THE SENSING ARM OF THE INTERFEROMETER, VARYING IN ACCORDANCE WITH TORSO EXPANSION AND CONTRACTION THAT ACCOMPANIES RESPIRATION. THE RESULT IS A CYCLIC OUTPUT SIGNAL THAT VARIES IN RELATION TO SUBJECT RESPIRATION. RESPIRATION SIGNALS WERE TAKEN SIMULTANEOUSLY FROM THE SAME SUBJECTS WITH THE INTERFEROMETER SYSTEM AND WITH A STANDARD POLYGRAPH PNEUMATIC SENSOR TO COMPARATIVELY TEST THEIR EFFECTIVENESS. BOTH SIGNALS GAVE ESSENTIALLY IDENTICAL RESPIRATION MONITORING INFORMATION AND WERE SUFFICIENTLY SIMILAR IN STRUCTURE TO PERMIT A PERSON TRAINED IN POLYGRAPH INTERPRETATION TO WORK READILY WITH THE INTERFEROMETER-DERIVED SIGNAL. ILLUSTRATIONS AND PHOTOGRAPHS ARE INCLUDED. (AUTHOR'S ABSTRACT MODIFIED--DEP)