Qed and the Men Who Made It: Dyson, Feynman, Schwinger, and TomonagaIn the 1930s, physics was in a crisis. There appeared to be no way to reconcile the new theory of quantum mechanics with Einstein's theory of relativity. Several approaches had been tried and had failed. In the post World War II period, four eminent physicists rose to the challenge and developed a calculable version of quantum electrodynamics (QED), probably the most successful theory in physics. This formulation of QED was pioneered by Freeman Dyson,