Dr. Quarrell has a long standing interest in Huntington's disease (HD). He has written peer reviewed papers and book chapters on the subject. He has been active member of the European Huntington's Disease Network and the UK Huntington's Prediction Consortium. He is an associate editor of the Journal of Huntington's Disease. He has been a principal investigator for a number of clinical trials of potential treatments for HD. For many years he served on the Executive Committee of the Hungtington's Disease Association (England and Wales): the first edition of this book was conceived whilst in this role.