Not for hypochondriacs or the squeamish. Kra assumes we are capable of absorbing a mass of information on the structure and chemistry of the brain, how it functions and ages; also how and why it sometimes malfunction. In older people, loss of memory coupled with confusion is sometimes misdiagnosed as irreversible senilitys The actual, cause may be treatable, and in successive chapters Kra deals with virtually all possible causes of brain impairment: how they are tested and disgnosed, their treatment and likely prognosis. He also deals with true dementia--the irreversible mental impairment produced by small strokes, some (but not all) cerebrovascular conditions, some viruses (e.g., syphillis and AIDS-related diseases), and degenerative diseases, most particularly Alzheimer's disease. Many older people suffering from memory loss fear they are becoming irreversibly senile and, says Kra, some have been institutionalized unnecessarily. Memory failure can be caused by a veritable host of conditions, including depression, treatable heart or lung diseases, chemical and blood deficiencies, medications, brain tumors, blood clots and so on. Some, of course, may be caused by currently untreatable ailments, among them AIDS-related brain viruses, small strokes, and Huntington's chorea. Alzheimer's disease:, which slowly and inexorably destroys the brain, has become increasingly prevalent. It is also currently untreatable and irreversible, Kra describes in concise detail the structural and chemical changes of the brain caused by this disease and gives a brief rundown on the present state of research on its cure or amelioration. But this one is that rata avis: a book on a medical problem that assumes the reader is intelligent enough to understand and evaluate a mass of complex information. Tough--but worth it.