Frederick Furniss, M.A., Ph.D., is an honorary clinical psychology teacher with the University of Leicester, U.K. He has more than 35 years of experience as a clinical psychologist working with children and adults with neurodevelopmental conditions, including extensive experience of assessment and intervention with people engaging in severe self-injury in both community and residential care settings. His clinical and research interests include assessment and intervention with self-injurious and restricted and repetitive behaviors and the relationships between cognitive and behavioral phenotypes in neurodevelopmental conditions. Asit B. Biswas, M.D., FRCPsych, MMedSci, DPM, is a Consultant Psychiatrist with the Leicestershire Partnership NHS Trust specializing in the assessment and management of autism, ADHD, and challenging behavior in people with intellectual disabilities, having worked with the UK National Health Service for more than 28 years. He is also an Honorary Associate Professor at the University of Leicester, U.K., and was past Chair of the Specialty Advisory Committee (Intellectual Disability Faculty, Royal College of Psychiatrists) responsible for curriculum development, and design of assessment structures and training pathways, for both Core and Higher specialist training in the Psychiatry of Intellectual Disability for doctors working towards completion of training to work as Consultants in this subspeciality in the UK. He has previously held the role of Training Programme Director in Psychiatry of Learning Disability at the East Midlands deanery. His clinical and research interests include management of challenging behavior, such as self-injurious behavior and aggression, in people with intellectual disability, autism and ADHD. He was a Principal Investigator for a recently completed project evaluating the clinical effectiveness and cost-effectiveness of Positive Behaviour Support for people with learning disabilityand challenging behavior funded by the U.K. National Institute of Health Research. He is currently the Vice-Chair of the Intellectual Disability Psychiatry Faculty, Royal College of Psychiatrists, London.