David A. Sinclair is a renowned biologist and professor of genetics at Harvard Medical School, specializing in the science of aging and longevity. He is best known for his groundbreaking research on sirtuins and NAD+ metabolism, which he extensively explores in his bestselling book "Lifespan: Why We Age—and Why We Don’t Have To." Sinclair's innovative approach has earned him recognition as a TIME 100 Most Influential People and the Australian Medical Research Medal.