At one time, biofeedback and behavioral medicine were considered synonymous, as evidence by Birk’s 1973 book, Biofeedback: Behavioral Medicine. As is obvious from the contents of this present book, behavioral medicine encompasses much, much more than biofeedback. However, as pointed out by Blanchard (1977), biofeedback is one important aspect of behavioral medicine. Much of behavioral medicine is concerned with changing gross, observable behavior. This can be accomplished either as direct treatment of a disorder with demonstrable pathophysiology, such as the treatment of obesity through modifying eating behavior and exercise patterns, or as an adjunct to standard medical treatment, such as improving medication-taking compliance in the drug treatment of hypertension. Biofeedback is somewhat different in that it represents psychological intervention delivered directly at the physiological level rather than at the level of gross motor behavior. Thus, in a sense, biofeedback could be seen as applied, or clinical, psychophysiology.