John Woolliams has been a recognised leader in the science of quantitative genetics applied to animal breeding for four decades. He has made important contributions in several key areas, including the development of the quantitative genetic theory that underlies key principles of modern breeding programs; applied research to solve practical problems in breeding programs; and the training and mentoring of numerous students and scientists, many of whom are now leaders in the field. He began his career in 1977 at the UK government-funded Animal Breeding Research Organisation (ABRO) in Edinburgh and continued working there through various reorganizations that led to the Roslin Institute, which is now part of the Royal (Dick) School of Veterinary Studies at the University of Edinburgh.