An explosion of new techniques to explore DNA and protein biology during the last 2 decades has illuminated one of the most enigmatic and intractable subjects in biomedicine-neuro degeneration. Eponymic diseases of the nervous system that were until recently characterized by mechanistic ignorance and therapeutic nihilism are falling steadily to the power of molecular genetics, cell biology, biochemistry, and animal modeling. Alzheimer, Huntington, Creutzfeld-Jacob, and Parkinson diseases, as well as amyotrophic lateral sclerosis, spinocerebellar atrophies, frontotemporal dementia, and other previously obscure diseases, have all yielded rapid progress in the deciphering of their biochemical pathology and genetic underpinnings. This sea change in our understanding of a group of incurable diseases that confer enormous personal and societal burdens has brought us to the verge of rationally designed therapies and, in some cases, into actual human trials.