The outstanding zoologist and teacher of zoology at Oxford from 1930 to 1945 was John Zachary Young (universally known as J.Z.). His research was of a distinction that led to his early election to the Royal Society in 1945. In the same year he became Professor of Anatomy and head of department, at University College London (UCL). There he reformed the basic teaching of medical students and built up a diverse and internationally distinguished research department. While at UCL (1945–74) he continued a significant personal research output, which went on for more than 20 years after retirement, first at the Wellcome Institute for the History of Medicine, then at the Department of Experimental Psychology, Oxford. In 1986 he was made an Honorary Fellow of the British Academy for his contributions as a Humanist. He published five books of lectures, about 250 research papers, numerous articles, a research monograph on the Octopus brain and four influential textbooks. He was a powerful and stimulating personality, a remarkable man by any measure, who enormously influenced generations of zoological and medical students through personal contact and through his writings and lectures.