"It is hard to believe it has been only 7 years since the publication of our first edition. In this short time, so much has changed in what we know about Parkinson's disease and how to treat it. As I read through the first edition, I found much information was already out of date within 4 years from publication. New knowledge about the role of protein misfolding and how it leads to nerve cell damage in Parkinson's, about when and where the disease...