The innovative theory articulated in Sources of Power: How Energy Forges Human History parses history into four ages: the foraging, agriculture, coal, and oil ages, each defined by the dominant source of power. Manfred Weissenbacher tests this sweeping theory against the panorama of world history, combining formidable powers of synthesis with a specialist's deep understanding of energy systems and technologies.After proving the operation of his law through history and into the present, Weissenbacher applies it to global geopolitical trends. He assesses the prospects of the various candidate technologies to succeed oil and charts future scenarios based on the distribution of energy reserves. Finally, he forecasts the fates of the American and Chinese empires in the twilight of the oil age: the United States as a mature superpower forced to deploy military might to occupy oilfields in the Middle East; China as an emerging superpower forced to deploy economic might to muscle in on the development of Third World oilfields.