By day, Claude Shannon labored on top-secret war projects at Bell Labs. By night, he worked out the details of information theory
Despite his dissatisfaction with defense work, Shannon had contributed to some important projects during the war and its immediate aftermath: projects in fire control, or the mechanization of antiaircraft artillery, and projects in cryptography that strengthened the secret transatlantic telephone line connecting FDR and Churchill.
But none of those projects had the impact of Shannon’s 1948 masterwork, “A Mathematical Theory of Communication” [PDF]. It was Pierce who best summed it up: “It came as a bomb.” It was stunning in its scope—he had conceived of a new science nearly from scratch—and stunning in its surprise—he had gone years barely speaking a word of it to anyone.