O'Halloran, Thomas J. · Public domain

Made a career of thinking rigorously about the unthinkable: as a strategist at RAND Corporation during the Cold War, he modeled how a nuclear war might unfold and argued that some outcomes were survivable, even "winnable" — the thesis of his 1960 book On Thermonuclear War. That analytical, unsentimental style made him one of the acknowledged models for the title character of Stanley Kubrick's Dr. Strangelove. He went on to co-found the Hudson Institute and become one of the era's most prominent futurists.