At the start of trade, there was addition and subtraction. There was money in the cash box and merchandise in the shop; they were there only at one particular stage in a succession of simple operations. Knowing what was coming in and what was going out, what one could sell and what one could pay—such were the rudiments of commercial management. Even so, needs began to differentiate on the basis of whether the merchant, artisan, or shopkeeper managed his own business, cash, and shop or was in charge of an appointed agent responsible to him. The need for an account book was hardly felt by the baker who, each evening, counted up the sous and deniers received for selling bread rolls at eight sous a dozen. Of course, bookkeeping would have given him the means to check his accounts, but for whom? against whom? If eight sous were missing from the cash box, whose fault could it be? The cutler knew exactly when he had sold his last knife and whether or not he needed to buy more blades from Germany or Normandy. The cloth merchant could see how much cloth he had left, and the spice merchant did not need an account book to notice that the sack of pepper was getting low.
As business developed and responsibilities were differentiated, bookkeeping provided the manager with a means of justifying his actions and the owner with a way to keep a permanent check on affairs. If stock increased and was distributed among several shops, no one would think of trying to manage the restocking just by looking at the shelves. As for the cash box, they would not leave it to guesswork to figure out who had paid and who