Mark L. Barr, M.D. is a tenured faculty member in the Division of Cardiothoracic Surgery at the University of Southern California (USC), Keck School of Medicine in Los Angeles and is Director of the USC Transplantation Institute. Dr. Barr has served as President of the International Society for Heart and Lung Transplantation (ISHLT), on the Board of Directors of the American Society of Transplantation and the American Society of Transplant Surgeons (ASTS), as Chair of the Thoracic Committee of the ASTS, and as the Program Chair for the Annual Scientific Meeting of both the ISHLT and the American Transplant Congress. He is the current Chair of the Advisory Committee on Transplantation (ACOT) for the Department of Health and Human Services and the Immediate Past Chair of the Thoracic Transplantation Committee of the United Network for Organ Sharing (UNOS). He serves on grant review committees for both the National Institute of Allergy and Infectious Diseases and the National Heart, Lung and Blood Institute of the National Institutes of Health, and is a Deputy Editor of the American Journal of Transplantation.