The experimental therapeutics of neurodegenerative disorders is in its infancy, but neuroprotective strategies are already being applied in healthy persons at high risk of developing disease as well as in patients with manifest illness, Knowledge of etiology and pathogenesis, improved design of clinical trials, the development of biological markers, the advent of genetic animal models, the enhanced identification of susceptibility factors, and more effective drug delivery-such advances have improved the prospects for forestalling onset of illness and clinical decline in the growing numbers of people affected by neurodegenerative disorders.