David W Holt BSc, PhD, DSc (Med), CSci, EuSpLM, FESC, FBPhS, FRCPath Emeritus Professor of Bioanalytics, St George’s, University of London, UK Associate Director - Analytical Services International Ltd, St George’s, London, UK Professor David Holt has more than 47 years’ experience in the measurement of drugs as a guide to therapy, and has been responsible for the development of assays used to monitor a wide variety of therapeutic agents. For over 20 years he was the Director of the Analytical Unit at St George’s, where he was also responsible for the analysis of illicit and prescription drugs for the Unit’s Forensic Toxicology Services provided to HM Coroners, pathologists and law enforcement agencies. He now advises on proficiency testing schemes for the measurement of immunosuppressive drugs, and on problems associated with substandard pharmaceuticals. Professor Holt is a frequent speaker on a broad range of issues relating to bioanalytics and clinical toxicology. He is the author of over 400 publications in peer reviewed journals and invited contributions to books. He is a past President of the International Association of Therapeutic Drug Monitoring and Clinical Toxicology and a recipient of the Charles E Pippenger Award for Outstanding Contributions to Therapeutic Drug Monitoring.