Peter Geymayer · Public domain

A German-American biochemist who mapped, step by step, how the human body builds cholesterol from a simple two-carbon molecule — a nearly thirty-step pathway that took over a decade of painstaking tracer work to establish. That research, done jointly with Feodor Lynen on the mechanism and regulation of cholesterol and fatty-acid metabolism, won them the 1964 Nobel Prize in Physiology or Medicine and became foundational to how cardiovascular disease and cholesterol-lowering drugs are understood today.