"This book represents a critical dissemination aid for countless men and women affected by PD who could find solace thanks to the HDT therapy." In 2011, the Italian neurologist Dr Antonio Costantini began treating his Parkinson's patients with high doses of B1. As a result, their symptoms improved by up to 70% with no obvious progression in the disease over the five years he worked with them. Yet there is still a lack of awareness about this valuable therapy amongst doctors and Parkinson's nurses. This book is intended for people with Parkinson's and their health professionals. It presents theories and hypotheses to explain the substantial effect thiamine has on the brain, discusses the available research which has studied the effect of high doses of B1 on Parkinson's patients, and details the protocol, as we currently understand it, for patients and doctors who wish to use the therapy. Parkinson's is a degenerative disease and consequently there is a sense of urgency for neurologists, doctors, and Parkinson's nurses to acquaint themselves with this therapy. This treatment is immediately available, relatively inexpensive and safe, and for many of us has improved our lives significantly. Sadly, in 2020 Dr Costantini died from Covid-19. However, his colleagues, wishing to continue his work, have designed a rigorous research project to understand more about the effect of high doses of thiamine on the Parkinson's brain. This in-depth research is needed before the therapy will be adopted by mainstream medicine. The research team have, however, been unable to procure funding to start this important study.