Professor Thomas Kirkwood is Professor of Medicine and Head of the Department of Gerontology at the University of Newcastle-Upon-Tyne. He is a mathematical biologist who has played a leading role in research into ageing since the mid 1970’s when he advanced the “disposable soma” theory of ageing. He has used Burke’s Peerage and Debrett to demonstrate in British aristocratic families, over many centuries, that human life histories involve a trade-off between longevity and reproduction. He was the BBC Reith Lecturer for 2001.