Dementia diseases are the most common cause of severe mental deterioration in the world today, and expected changes in the population structure will inevitably result in a gradually increasing occurrence of dementia. One of the primary symptoms of dementia diseases is severe memory dysfunction. Knowledge about the ways in which dementia diseases affect memory increases our knowledge about the relationship between brain structures and memory functions, is imperative for early clinical diagnosis, and forms a basis for sound behavioral and pharmacological intervention. While the memory impairment in dementia has been known for more than 2000 years, the nature of this impairment is not yet completely understood. Research in this area has not, until quite recently, utilized theoretical and methodological advances from basic cognitive psychology. This volume gives a comprehensive treatment of this new and increasingly developing field of inquiry.