This book examines the latest research in brain-derived neurotrophic factor (BDNF) in Huntington's Disease, in the treatment of diminished glutamatergic signaling in schizophrenia; its role in cognition and treatment response; its importance in the normal course of brain development in which abnormal BDNF expression during critical developmental periods has been increasingly linked to autistic pathology; and finally, a review of proBDNF intracellular and extracellular processing, transport, signaling mechanisms as well as its biological function in health and disease.