John Hermon-Taylor studied medicine at Cambridge University and at the Royal London Hospital, London UK. He subsequently proceeded to higher surgical training in London, and obtained the Mastership of Surgery degree by Thesis at Cambridge. He spent a year 1968-69 as a Medical Research Council Clinical Research Fellow in the Department of Gastrointestinal Physiology at the Mayo Clinic. On returning to London he took up a position as Associate Professor in Surgery, London University and was appointed to the Chair of Surgery at St. George's Hospital and Medical School in 1976. He set up a laboratory of molecular biology in the Department of Surgery at St. George's in the early 1980's, and has applied these methods to the study of Crohn's disease. He currently leads an active research group in the field and a clinical team specializing in the treatment and ongoing care of patients with Crohn's disease. The principal clinical objective is the development of a multi-subunit therapeutic vaccine incorporating DNA and protein technologies, based upon specific genes from Mycobacterium avium subsp. paratuberculosis, to accelerate immune-mediated microbial clearance in Crohn's disease sufferers.