One of the greatest economic thinkers of all time has already left us. He will definitely be missed, students and fellow economists alike. I'm sure you've already seen the many online news articles that celebrate his accomplishments in life. He was the first John Bates Clark winner, and the first American Nobel Laureate in Economics. For me, I think his greatest contribution is helping create the "Neoclassical synthesis," the current mainstream field of economics that incorporates both neoclassical principles with Keynsian ones.