Donald I. Abrams, MD, is Professor of Clinical Medicine and Director of Clinical Programs, UCSF Osher Center for Integrative Medicine, University of California, San Francisco; and Chief of Hematology-Oncology, San Francisco General Hospital. Andrew Weil, MD, is Lovell-Jones Professor of Integrative Rheumatology, Clinical Professor of Medicine, Professor of Public Health, and Director of the Arizona Center for Integrative Medicine, University of Arizona. He is the best-selling author of Healthy Aging.