A typical phenomenon of industrial economic systems observed in the long run is in fact the change of the structure of the system; that is, the change of the composition of its main magnitudes along with the change in their absolute levels. The phenomenon of structural change immediately emerges if people compare the shares of value added and of employment with reference to the three macro-sectors of a group of selected countries over a sufficiently long time horizon. The data display a sharp structural change of the economies observed over an interval of roughly 30 years. The share of value added in industry increases only in some lesser developed countries; it remains almost constant in India and decreases in all other countries. Smith, for example, stressed the increasing weight of’productive’ with respect to ‘unproductive’ labour, emphasizing thus a structural dynamics of employment.