Whereas the Protestant Ethic essays are mainly concerned with the nature and origins of the modern capitalist spirit, Weber's concept of modern capitalism comprises a far wider set of components. In his General Economic History, six features are listed. These are rational capital accounting, free markets, rational technology, "that is one reduced to calculation to the largest possible degree, which implies mechanisation", calculable law, free wage-labour, and the commercialisation of economic life (1923, p. 208).