Nerve endings in the walls of the carotid sinuses and the aortic arch transduce arterial pressure changes and provide the central nervous system with a steady stream of encoded information. On the basis of this information, efferent autonomic neural activity is modulated finely, and the neurohumoral milieu of the heart and the blood vessels is adjusted on a second-to-second basis. The arterial baroreflex may be the most important of the cardiovascular control mechanisms, because the baroreflex, above all other reflex mechanisms, is the one whose speed is most adequate to respond rapidly to the abrupt transients of arterial pressure that occur in daily life. This volume presents the many experimental methods available for use in humans that have been recently developed. Some are ingenious and yield results that earlier might have been thought impossible to obtain from human volunteers. Development of these new methods has increased the scientific credibility of human baroreflex research, and this work discusses the advances made in these studies. It clearly describes the existing deficiencies in the understanding of baroreflex mechanisms, and suggests methods for future research in this developing field.