This review traces the heretofore unsung hero role of engineering in the evolution of today's healthcare and the growing bond between physics, engineering, and medicine. It recognizes the debt owed to the various specialties of healthcare engineering, especially the bioengineers who contribute not only to a better understanding of basic physiologic and pathologic processes but also to the development and application of technology and the adaptation of new engineering discoveries to medicine. In the past half-millennium, the fields of physics, engineering, and medicine have made a large number of seminal contributions to each other, resulting in ever-advancing healthcare methodologies, although only a precious few remain identified by the originators' names. In this review, 3 engineers are cited in detail for their milestone contributions to medical progress: Roentgen in radiology, Bovie in electrosurgery, and, more recently, Greatbatch in implantable cardiac pacemakers. Future horizons in medicine appear to be ever more attainable because of the synergism between the physical and biological sciences.