Progress in the diagnosis, treatment, and prevention of Alzheimer?s Disease (AD) depends critically on the availability of large ?trial-ready? cohorts of participants spanning the transition from normal through preclinical AD stages, mild cognitive impairment (MCI), to early AD. The PITT-ADRC Clinical Core has effectively accomplished this, evaluating a cohort of more than 4700 participants since its inception and providing participants, biologic samples, and data for a wide array of studies that depend critically on differing clinical populations: participants at risk for AD (e.g. prevention, biomarker studies); participants with clinical AD (e.g. GWAS of AD, GWAS of psychosis); participants with autopsy-confirmed AD (e.g. postmortem-tissue studies); and participants with other dementias (e.g. DLB consortium). The Clinical Core has developed approaches to maximize flexibility in meeting the needs of these diverse, and evolving, set of supported investigations. In addition to its role as a critical resource for many funded studies in the PITT-ADRC, the Clinical Core will provide participants that will serve as a focus for biomarker evaluation by the Neuroimaging Core and the Biomarker and Neurogenetics Core. During the current period we have also maintained our strong history of neuropsychiatric characterization of all participants and further enhanced our rate of autopsy consent, supporting the Neuropathology Core and multiple affiliated R01s. We have continued our strong record of providing genetic samples and data on large numbers of participants annually for use in local R01s and in national and international consortia. Finally, we have added new investigators with specialized expertise in Parkinsonian syndromes and FTLD and have developed new procedures to increase the rate of completed follow-up visits for our participants. These accomplishments have prepared the Clinical Core to maintain its productivity in the following set of proposed Specific Aims: 1) To perform evaluations at study entry and at annual follow-up of Normal Control, pre-MCI, MCI, AD, and related dementia participants participating in the PITT-ADRC; 2) To assure maximum participation in clinical, intervention, brain imaging, biomarker, and autopsy studies by providing appropriate research study referrals and clinical services during longitudinal follow-up; 3) To provide clinical data, research participants, DNA samples, and technical and scientific leadership to support new and ongoing research projects at the PITT-ADRC, within and outside the University of Pittsburgh, and to support national consortium studies; 4) In collaboration with the Outreach, Recruitment, and Engagement Core, to facilitate recruitment and retention of diverse participants; 5) To support the Research and Education Component in training the next generation of dementia researchers by providing research participants, samples, and data.