The salesman represents the only element in modern business which we can go on improving indefinitely.
The salesman is the only factor in the production end of the business which can be improved almost without limit.
There is a technical limitation which sometimes determines how far we can go on improving our product, but there is no technical limitation to developing the minds, educating the souls, and improving the spirits of the salesmen. — M.O. Maughan 1929 
