Tom Williams is Chair in Haemoglobinopathy Research at Imperial College London. He is a paediatrician and global leader in haemoglobin research who has made outstanding contributions to the understanding of human genetic resistance to malaria. He co-conceived and leads the largest demographic and health surveillance system in Africa and runs an active programme of genetic research throughout the region. Professor Williams’ work has led directly to changes in international policy regarding the prevention and management of bacterial infections and malaria in African children with sickle cell disease, and has played a major contribution to the improving profile of this condition on the international health agenda.