Bengt Nyman · CC BY 2.0

Alvin Roth turned game theory into working machinery: his research on market design showed how to build systems — kidney-exchange programs, school-assignment algorithms, medical residency matching — that pair people efficiently in situations where ordinary prices can't be used to clear the market. He shared the 2012 Nobel Memorial Prize in Economic Sciences with Lloyd Shapley for the theory of stable allocations and its practical application, and served as president of the American Economic Association in 2017. His work sits at the unusual intersection of abstract theory and direct, immediate consequence for real people's lives.