Contrary to common impression, global energy use in the 19th century was dominated by wood, not coal; and in the 20th century by coal, not oil. Not until 1964 did oil overtake coal as the world's prime mover. Even today, coal provides the world more energy than natural gas. Energy Transitions: History, Requirements, Prospects shows that any energy transition -- the interval between the introduction of a new primary energy source and its rise to 20-30 percent of a national or global energy market -- takes decades or even centuries. Energy transitions are inherently complex and intractably prolonged affairs. Despite the well-nigh universal acceptance of the cogency and urgency of the need for human civilization to wean itself from its primary dependence on fossil fuels, there is no similarly broad acceptance of the fact that our energy transition to carbon-neutral and renewable energy sources must unfold on the scale of decades, not years. This book describes the history of modern society's dependence on fossil fuels and the prospects for the transition to a nonfossil world. Vaclav Smil makes it clear that this transition will not be accomplished easily, and that it cannot be accomplished within the timetables established by the Obama administration. - Publisher.