Definitive diagnosis of Alzheimer's disease requires postmortem examination of human brain tissue. The Neuropathology Core (Core C) is an essential part of the Bryan ADRC. Investigators must know whether a given individual was suffering from AD alone, AD in combination with another dementing illness or from a non-AD dementia to appropriately evaluate clinical diagnostic and therapeutic trials. Postmortem examination of clinically affected and non -affected family members as well as non-related normal controls is required for genetic studies of AD and also serves as an aid in evaluation of preventative and therapeutic measures. Since there is no widely available animal model for this illness, researchers at the Bryan ADRC and other institutions require human brain tissue for biochemical, molecular and histological studies. The Neuropathology Core is designed to meet three specific aims; (1) Provide fresh brain tissue from AD patients and controls within 30-60 minutes after death: (2) Establish neuropathological diagnoses, dissect and store brain tissue from demented and neurologically normal control patients for dissemination to investigators internal and external to Duke: (3) Coordinate a routing service for histological, neuropathological and neurochemical data through the Clinical Research Development and Informatics Cores. To adequately meet the many diagnostic and research needs of the Bryan ADRC Rapid Autopsy Protocol and the Brain Endowment Brain Endowment Bank at the University of Miami (UM) School of Medicine. The latter site has the unique capability of securing large numbers of control specimens. There are now standardized protocols in place for the acquisition of neuropathological specimens at athe two sites. The Duke neuropathology staff provide coordination and administrative oversight for the two sites. For uniformity, assignation of neuropathological diagnoses are also coordinated through the Duke site. The overall goal of the neuropathology Core continues to be the combining of the strengths at the two sites to accomplish the following aims; (1) Continue the active enrollment of patients and controls in the Rapid Autopsy Protocol (RAP) at Duke; (2) Continue development of the Miami normal tissue resource, allowing distribution of well-characterized controls to internal and external investigators for clinical and basic science research studies; (3) Provide uniform neuropathologic diagnoses for the demented patients and controls enrolled at the Duke and UM research sites: and (4) Coordinate release of specimens to qualified investigators according to the Bryan ADRC guidelines.