John Axford is a Consultant in Adult and Paediatric Rheumatology and Emeritus Professor of Clinical Rheumatology at St George's, University of London. After training at University College Hospital he worked at The National Hospital for Neurology, The Hammersmith Hospital, The Royal Brompton Hospital, Kings College Hospital and the New England Medical Center Boston USA He has enjoyed teaching medicine throughout his career and pioneered video teaching to developing countries with the Royal Society of medicine. He is an author and editor of the textbook UpToDate. Chris O’Callaghan is Professor of Medicine at the University of Oxford and a Consultant Physician (in Acute General Medicine) and Consultant Nephrologist in the Oxford University Hospitals. He is Chief Examiner in Medicine for the University of Oxford, runs a research group, teaches medical students, and is a Fellow and former Dean of The Queens’ College, Oxford. After training and working in Oxford he worked at Guy’s, St Thomas’, Hammersmith, Brompton and Lewisham hospitals in London, Royal Stoke University Hospital, the University of California, San Francisco and the California Institute of Technology. His other books include The Kidney at a Glance and The MRCP Part I: a System Based Tutorial.