Alzheimer's disease is a progressive neurodegenerative disorder that affects memory, thinking, and behavior. It is the most common cause of dementia, accounting for 60-80% of cases. The disease typically starts with mild memory loss and confusion, which worsens over time, leading to severe cognitive decline and the inability to perform daily tasks. Alzheimer's is characterized by the buildup of abnormal proteins, such as amyloid plaques and tau tangles, in the brain, which disrupt nerve cell communication. While the exact cause is unknown, age, genetics, and environmental factors are believed to play a role in its development. Currently, there is no cure for Alzheimer's, but medications and therapies can help manage symptoms. Early diagnosis and intervention can improve quality of life and slow the progression of the disease.