Five papers representing different frames of reference examine the question 'What is Military Psychology?' Their objective is to ferret out the unique aspects of psychology as its is practiced in the military environment that differentiate it from research in, and applications of, psychology in other settings. The purpose in doing this is to sharpen the focus and improve the products of military psychology. Areas examined cover (1) human-machine systems, (2) military personnel, training, and organizational effectives; (3) psychological operations/warfare and the area of 'hearts and minds'; (4) community mental health, consultation to command, and the psychologist in uniform; and (5) stress, fitness, and the relationships of military psychology with its neighboring disciplines in the biomedical sciences. Constraints and ethical considerations in the use of psychology in the military environment and in the pursuit of military objectives are considered. (Author)