Parkinson's Disease has traditionally been seen as a movement disorder, and diagnosed by the development of tremor. However, we are beginning to understand that the disease manifests itself in many ways, and that earlier diagnosis might be possible through non-tremor symptoms. This textbook aims to tell the full story of non-motor and non-dopaminergic features of Parkinson's Disease.About the Author: C. Warren Olanow, MD, FRCPC, Departments of Neurology and Neuroscience, Mount Sinai School of Medicine, New York, NY, USA Fabrizio Stocchi, MD Institute of Neurology, IRCCS San Raffaele Pisana, Rome, Italy Anthony E. Lang, MD, Division of Neurology, University of Toronto, Toronto, Canada