Alois Alzheimer was a German psychiatrist and neurologist born on June 14, 1864. He is best known for his research on Alzheimer's disease, a progressive neurological disorder that affects memory and cognitive function. In 1901, he observed a patient named Auguste Deter, whose symptoms led him to identify the condition that would later bear his name. Alzheimer's work included studying brain tissue and identifying abnormal protein deposits, known as amyloid plaques and neurofibrillary tangles, which are characteristic of the disease. His findings laid the groundwork for understanding dementia and have significantly influenced modern neuroscience and geriatric medicine.