Simon Shorvon MA MB BChir MD FRCP Professor in Clinical Neurology and Clinical Sub Dean, UCL Institute of Neurology, University College London and Consultant Neurologist, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK Emilio Perucca MD Ph D FRCP(Edin) Professor of Medical Pharmacology, Clinical Pharmacology Unit, Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy; and Director, Clinical Trial Center, C Mondino National Neurological Institute, Pavia, Italy Jerome Engel Jr MD Ph D Director, Seizure Disorder Center, Jonathan Sinay Distinguished Professor, Neurology, Neurobiology, Psychiatry and Behavioural Sciences, David Geffen School of Medicine at UCLA, Los Angeles, California, USA