Huntington's disease (HD) is a heredodegenerative disease of the central nervous system (CNS) characterized by progressive motor and mental alterations. The unique neuropsychiatric characteristics of HD have fascinated researchers in the fields of neurology, psychiatry, genetics, and basic neuroscience since the beginning of this century. A great deal of knowledge about HD has accumulated worldwide, especially since the 1970s, culminating in the discovery of its genetic defect at the start of the 1990s. Current efforts are centered on the search for treatment options to change the prognosis for affected individuals and families. The key historical, epidemiologic, clinical, diagnostic, genetic, pathophysiologic, and therapeutic aspects are reviewed.