With a BSc degree in Zoology (Birmingham 1947)Ruth Bellairs moved to UCL (University College London) and obtained a PhD under the joint supervision of Sir Gavin de Beer and Michael Abercrombie. She joined the academic staff of the Department of Anatomy and Embryology (now Cell and Developmental Biology) in 1949 and, apart from short periods in the University of Cambridge and St Bartholomew's Hospital Medical College, remained there. During this time she taught medical and science students and supervised PhD students. Now officially retired, she continues in an honorary capacity as Professor Emeritus. She has published about 150 research papers, mostly concerned with the chick embryo and involving experimental microsurgery, tissue culture, transmission and scanning electron microscopy, and molecular biology,the aim being always to understand more about the interacting forces that promote the orderly differentiation of a developing embryo. Many of the projects involved international collaboration. She served on the editorial board of several journals,including JEEM (now Development) for about 10 years, and Anatomy and Embryology for 20 years, and was involved in organising international conferences in the Europe, North America and Asia. She was married to the herpetologist, A.d'A. Bellairs, who died in 1990.