This work studies the historical transition from the agrarian solar energy regime to the use of fossil energy, which has fuelled the industrial transformation of the last 200 years. The author argues that the analysis of historical energy systems provides an explanation for the basic patterns of different social formations. It is the availability of free energy that defines the framework within which socio-metabolic processes can take place. This thesis explains why the industrial revolution started in Britain, where coal was readily available and firewood already depleted or difficult to transport, whereas Germany, with its huge forests next to rivers, was much longer dependent on a traditional solar energy regime."