At the start of Bletchley park in the 2nd world war, the code-breakers were thought to have little to contribute to the war effort and so were dismissed by top brass. However, after cracking enigma and the Luens scyther (pardon my spelling) etc. they managed to intercept such important messages as the German battle plans for the battle of Kursk and pass them onto the Russians. To me, these acts are the most important things to be contributed to the war. Also Alan Turing and Tommy Flowers who contributed ideas to this computer age. Anyone have anything else to contribute to this thread?