The very name Alzheimer is sure to bring a shudder. Thirty to forty million people are now afflicted with Alzheimer's disease, a degenerative brain disorder that strips its victims of their identity and leaves families bereft and social services strained. Despite considerable research, the underlying causes of Alzheimer's disease remain shrouded in mystery. So, too, does the man after whom it was named. Alois Alzheimer (1864--1915) was practicing medicine at the Frankfurt Asylum in 1901 when he met a patient, who would become known as "Auguste D.," whose condition perplexed and intrigued him. "Alzheimer" is more than a biography; it is a story of scientific discovery at a crucial stage in the history of medical psychiatry.