Core B: Clinical supports the Adult Children Study Program Project Grant by recruiting, enrolling and longitudinally following adult children, age 45-74 years at entry, of parents with and without symptomatic Alzheimer disease. ACS participants age 45-64y will have clinical and psychometric assessments at entry and every 3 years thereafter (annually for ACS participants ≥65y). The Core is essential in that it supplies carefully characterized participants to all relevant Cores and Projects. The Clinical Core interacts directly or indirectly on a daily basis with virtually every facet of the ACS PPG. The functions of the Core are to: 1. Recruit, enroll, and maintain the ACS cohort at ~300 active participants to support the Projects in this application. Twenty-five new participants <65y will be enrolled each year to replenish the younger groups due to aging into the ≥65y group. 2. Comprehensively assess the ACS participants with well-established clinical and psychometric instruments at entry and every three years (annually for participants ≥65 years of age). 3. Obtain blood at the initial assessment from all participants for apolipoprotein E (APOE) genotyping and banking of extracted DNA and plasma (supported by the Knight ADRC Genetics Core). 4. Coordinate the participation of ACS participants in the procedures of the Biomarker Core and all Projects: Project 1 – Preclinical Predictors of Progression from Cognitive Normality to Impairment Project 2 – CSF Biomarkers of AD Progression Project 3 – Attentional Control, Sleep, and Memory Consolidation: The Role of AD Biomarkers Project 4 – Dynamic Ordering of Imaging Biomarkers in Preclinical AD 5. Integrate all Core data with the DMBC, and interact cooperatively with all components of the PPG. 6. Encourage the retention of ACS participants by safeguarding their research data, monitoring the participants’ burden as they complete the protocols of the Cores and Projects, annually sharing with them research results, and soliciting their input into the aims and operations of the ACS.