The Comparative Effectiveness Dementia & Alzheimer's Registry (CEDAR) Project is a prospective registry of adult patients at-risk for, or with, a diagnosis of dementia due to Alzheimer's disease (AD). The purpose of this study is to develop a research repository, or database, for information collected during routine medical care of people with normal memory and family history of AD, or with memory loss or other changes in thinking. The registry will help generate empirical evidence that improves knowledge and informs care decisions about risk reduction for dementia due to AD, and about the effectiveness of a clinical precision medicine intervention. Using a life course approach to comparative effectiveness research will enable investigators to analyze the effects of evidence-based multi-domain interventions on cognition, biomarkers of AD risk, and calculated AD risk across the pre-dementia spectrum of AD.