This book provides an extensive account of various diseases, such as Parkinson's disease, prion disease, motor neuron diseases like multiple sclerosis and spinal muscular atrophy. It also offers a profound explanation of various neurodegenerative diseases with novel theories of understanding the etiology, pathological mechanisms, drug screening methodology and new therapeutic interventions. It discusses how hormones and health food supplements influence disease progression of neurodegenerative diseases and it also deals with the collection of prion proteins in prion diseases along with discussing application of stem cells. This book is appropriate for various people: college students can utilize it as a textbook; researchers in academic institutions; pharmaceutical companies can use it as an up-to-date account of research information; health care professionals can take it as a reference book, and patients' families, relatives and friends can refer to it as a good means to understand neurodegenerative diseases.