Traditional psychophysiological stress research has been limited to the laboratory because of the nature of the equipment necessary. The real world validity of such research is questionable, making epidemiological field studies necessary if such data are to be used effectively in developing improved diagnostic and preventive intervention procedures. The lack of a truly portable psychophysiology microlaboratory appears to be the major impediment to conducting these important field studies. The ideal "microlab" would be a fully computerized, energy efficient, truly portable version of the traditional psychophysiology laboratory. This means that such a microlab would be capable of stimulus generation, measurement of multiple parameters of psychophysiological reactivity to stress, reduction of psychophysiological data, and transmission of digitized data to mainframe computers in file compatible formats. The proposed research is to determine the feasibility of developing such a microlab for use in field studies of psychophysiological reactivity to stress. This proposal is relevant to two topics solicited by the NHLBI: 1) Development of instrumentation for biobehavioral research 2) Development of procedures for standardized assessment of stress and behavior.