For most people, joining the In-Clinic phase of the study will require visiting a clinical site for one or two days each year. Participants will be busy on those days they are at the clinic. Participants will be asked a lot of questions about themself and their health, and will take different thinking and memory tests. Different samples such as urine, blood, or cerebrospinal fluid (CSF which involves a lumbar puncture procedure) will be taken by specially trained staff. Brain imaging scans (MRI and PET) can take a few hours to complete. We appreciate the time and generosity of the people who choose to participate in ADNI. We realize your time is valuable and we only include tests and procedures that we think will provide the best information for scientists working on Alzheimer’s disease.