Hugh Makin obtained his PhD at the institute of Child Health, University of London in 1966 and was awarded the degree DSc in 1996 for his research on steroid analysis. He has been successively Lecturer, Senior Lecturer and Professor in the Department of Clinical Biochemistry at St. Bartholomew's & the Royal London School of Medicine & Dentistry since joining the Medical School in 1967. His research interests involve the use of for the measurement of vitamin D metabolites and, in collaboration with Glen Jones, the use of mass spectrometry for the identification of calcitriol analogue metabolites both in vivo and in vitro.Hugh was the Programme Adviser to the UK Food Standards Agency Phytoestrogen Research Programme which supported a phytoestrogen quality assurance scheme organised by the Institute of Food Research in Norwich.D.B.Gower is Emeritus Professor of Steroid Biochemistry in the University of London, United Kingdom. He holds a B.Sc. in Chemistry(1955) and a Ph.D. in Biochemistry(1959) from the University of London and in 1972 he was awarded a D.Sc (Lond.) for his research into the biochemical mechanisms for the control of steroid hormone formation and the pheromonal properties of some C19 steroids. His University teaching and research career began in 1960 at Guy's Hospital Medical School, London and in 1986, he was promoted to Professor and Vice-Chairman of the Division of Biochemistry in the United Medical and Dental Schools of Guy's and St. Thomas's (now merged with King's College London).Professor Gower is a Chartered Chemist and Fellow of the Royal Society of Chemistry as well as a Chartered Biologist and Fellow of The Institute of Biology.