I have loved archaeology since middle school and have spent many vacations dragging my wife and kids around the world visiting ancient ruins—from the Anasazi kivas of the American Southwest to the “lost cities” of Machu Picchu and Petra to the big-headed Moai statues towering over Easter Island. Somewhere along the way, medical school and a neurology residency derailed my affair with the subject. But even now I sometimes imagine myself as a brain archaeologist—delicately picking through preserved specimens, cataloguing biological artifacts and trying to align my findings with people's unique histories. I am lucky to have had plenty of opportunity to indulge this daydream. At the Rush Alzheimer's Disease Center in Chicago, where I am director, about 100 scientists are searching for ways to treat and prevent a range of common neurodegenerative disorders. For nearly a quarter of a century I have led two longitudinal investigations—the Religious Orders Study and the Rush Memory and Aging Project—which have enrolled more than 3,350 older adults across the U.S. Our volunteers enter these studies, dementia-free, anywhere from their mid-50s to their 100s and, remarkably, agree to hours of testing each year. They undergo comprehensive physical examinations, detailed interviews, cognitive testing, blood draws and, in some cases, brain scans. Most important, all of them donate their brain after death to our research. The resulting collection fills various cabinets and two “freezer farms”—maintained at −112 degrees Fahrenheit and protected by backup and alarm systems—covering about 4,000 square feet.