Still Alice by Lisa Genova

At 50, Dr. Alice Howland is at the top of her game, professionally. A psychology professor at Harvard, she travels the world, speaking about her research. Her world is turned upside down when she receives the news that she's suffering from early-onset Alzheimer's. Alice and her family (husband, John, and adult children, Anna, Tom, and Lydia) are stunned by the news and have to learn to cope with the diagnosis and how it will change all their lives. Told through Alice's eyes as she descends into dementia, Still Alice is a powerful, poignant story of that journey.