The beginnings of lean, written about in 1926.
“Take a vein in a coal mine. As long as it remains in the mine, it is of no importance, but when a chunk of that coal has been mined and set down in Detroit, it becomes a thing of importance, because then it represents a certain amount of the labor of men used in its mining and transportation. If we waste that bit of coal – which is another way of saying if we do not put it to its full use – then we waste the time and energy of men. A man cannot be paid much for producing something which is to be wasted.”
–Chapter 8, “Learning from Waste”.