During the 20th century, Economic History grew into one of the main sub-disciplines of the Historical and Economic Sciences. Its roots can be traced back to the 18th and 19th centuries: mercantilists as well as classical economists, and later the German and English Historical Schools, they all were already using economic-historical data to support their reflections and theories. During the inter-war period, quantification was added as an analytical tool. Immediately after the Second World War, research focused mainly on macro-economic problems, with some American scholars during this period introducing a ‘New Economic History’, Cliometrics. From the mid-1970s onwards, the interest shifted increasingly to micro-economic questions, to be interpreted as a positive movement. The shift, indeed, creates a potential for a future combination of macro- and micro-approaches in Economic History. Such a combination would stimulate the integration of the three main variables of economic life and development (structure, hazard and freedom) into a more meaningful explanatory synthesis.