The editors have divided the text loosely into three parts. The first reviews the history, definition, epidemiology, diagnosis, classification, and strategies for early identification. They note that age is the single most important risk factor. Family history, certain genetic variations (e.g., APOE, E4 homozygotes), and depression are also important predisposing factors that may increase the risk substantially. Conversely, there is preliminary evidence indicating that such disparate factors as regular physical activity; the use of wine, coffee, statins, nonsteroidal antiinflammatory drugs, certain vitamins (e.g., C and E); and higher educational attainment (as well as length of training) may reduce the risk of dementia.