How can you adequately honor a man of deeds with mere words? Dr. Donald Eaton Gregg is recognized throughout the scientific world for his distinguished contributions to our knowledge of the coronary circulation, his advances in experimental instrumentation and design, his scientific integrity and his lasting influence on other investigators. His research associates over the years are now liberally scattered over the entire world. Their accomplishments and activities reflect the quality of their training in his Department of Cardiorespiratory Diseases at the Walter Reed Army Institute of Research. The positions of prestige occupied by these men attest to Dr. Gregg's ability to select and inspire men of talent, yet in his usual modest way he insists that he was only fortunate to be in the right place at the right time. Thus, at the time of Dr. Gregg's retirement as Chief of the Department of Cardiorespiratory Diseases, a position he has held since 1950, his associates thought that a scientific symposium was the most appropriate way to honor a man of his stature. Accordingly, on March 29-30, 1973 a Symposium on Current Topics in Coronary Research was held at the Walter Reed Army Institute of Research. Its objectives were to define our present state of knowledge and, more importantly, define the basic questions requiring further experimentation in four major areas of coronary research, i. e.