BRADLEY J. WILLCOX, M.D., M.Sc., is an internist and a geriatrics fellow in the Division on Aging at Harvard Medical School. He is also a resident scholar at the University of the Ryukyus in Okinawa, Japan, and a co-investigator of the Okinawa Centenarian Study. D. CRAIG WILLCOX, Ph.D., is a medical anthropologist and a gerontologist. He is an assistant professor at Okinawa Prefectural University–College of Nursing and a co-investigator of the Okinawa Centenarian Study. The Willcoxes are identical twins. MAKOTO SUZUKI, M.D., Ph.D., is a cardiologist and a geriatrician. He is on the faculties of the University of the Ryukyus in Okinawa International University. He is the principal investigator of the Okinawa Centenarian Study.