You’ve probably never heard of him unless you are a logician or logic groupie (Muffti has yet to verify the existence of the latter!), but Paul Cohen was a leading logician and mathematician. He passed away at 72. He spent most of his career teaching at Stanford. In his time, he won two of the most prestigious math awards in the world: the Bocher prize (1964) and the Fields Medal (1966). He showed that (augmenting work by Kurt Godel) that the Continuum Hypothesis was independent of Zermelo Frankel set theory, along with other important work (on the axiom of choice, for example). He was inventor of a mathematical technique known as ‘forcing’.
The Stanford obituary can be seen here.