Dr. Marr graduated from Xavier University in Cincinnati, OH in 1959 (BS), from the Johns Hopkins University School of Medicine in 1964 (MD), and St. Louis University in 1970 (MS-biochemistry). Board certified in internal medicine and  infectious diseases. The first half of his career was in academic medicine where he held positions of Professor of Medicine, Microbiology, and Biochemistry. He then entered into executive management of pharmaceutical and biotechnology companies and then joined Pacific Rim Ventures,an international venture capital firm. He recently published a book entitled Fall from Grace, a history of the past fifty years of medicine and social change in the US.