World Economic Forum · CC BY-SA 2.0

Gell-Mann gave particle physics its organizing vocabulary, proposing quarks as the fundamental constituents of protons, neutrons and the other strongly interacting particles, and later helping develop quantum chromodynamics to describe how they're bound together. That work on classifying elementary particles and their interactions won him the 1969 Nobel Prize in Physics, and his introduction of the renormalization group became a foundational tool across quantum field theory and statistical mechanics alike.