Adel A.F. Mahmoud, M.D., Ph.D ., is President of Merck Vaccines at Merck & Co., Inc. He formerly served Case Western Reserve University and University Hospitals of Cleveland as Chairman of Medicine and Physician-in-Chief from 1987 to 1998. Born in Cairo, Egypt, Dr. Mahmoud received his M.D. degree from the University of Cairo. He completed training at the teaching hospitals of the University of Cairo and joined the Faculty at Ain Shams University in Cairo, Egypt. Dr. Mahmoud was selected a WHO fellow to study for the Ph.D. degree at the University of London, School of Hygiene and Tropical Medicine which he was awarded in 1971. Dr. Mahmoud conducted investigations on the biology and function of eosinophils. He prepared the first specific anti-eosinophil serum, which was used to define the role of these cells in host resistance to helminthic infections. Dr. Mahmoud also established clinical and laboratory investigations in Kenya, Egypt and The Philippines to examine the determinants of infection and disease in schistosomiasis and other infectious agents. This work led to the development of innovative strategies to control those infections, which have been adopted by the World Health Organization as selective population chemotherapy. Dr. Mahmoud turned his attention to developing a comprehensive set of responses to the problems associated with Emerging Infections and the need to expand immunization and the reach of vaccines in the developing world. Dr. Mahmoud was elected to membership of the American Society for Clinical Investigation in 1978, the Association of American Physicians in 1980 and the Institute of Medicine of the National Academy of Sciences in 1987.