John Timbrell is Glaxo Professor of Toxicology at the School of Pharmacy, University of London. He has extensive teaching experience in toxicology at both undergraduate and postgraduate levels and is the author of the popular textbooks Principles of Biochemical Toxicology, 2nd edition (Taylor & Francis, 1991) and Introduction to Toxicology, 2nd edition (Taylor & Francis, 1995). He is also an examiner for the Diploma of the Institute of Biology in Toxicology.