Leo Szilard

Born in Budapest in 1898, Szilard studied engineering until World War I interrupted, then fled to Berlin and switched to physics, writing his doctoral thesis on Maxwell's demon and becoming the first to link thermodynamics with information theory. He filed early patents for the electron microscope and cyclotron, worked with Einstein on a refrigerator, then got out of Germany in 1933 the moment Hitler took power. In England he helped refugee scholars escape; in America by 1938 he was working with Fermi on chain reactions, present in the room when Chicago Pile-1 went critical in December 1942. He drafted the petition to demonstrate the bomb without killing civilians - the Interim Committee ignored it. After the war he sounded alarms about salted thermonuclear weapons, pivoted to biology and discovered feedback inhibition, helped clone the first human cell, and founded the Council for a Livable World in 1962 to argue against the weapons he'd helped invent. He died of a heart attack in 1964.