History offers a useful, though often neglected, longrun perspective on current energy problems. Of particular interest to those who seek to analyze the coming transition from petroleum to alternative sources of energy is the history of the transition from coal to oil in the early part of the twentieth century. The first stage in the ascent of oil culminated after World War X, when the demand for gasoline expanded rapidly in response to a dramatic increase in the use of motor vehicles. But even before the surge in gasoline consumption in the 1920s, oil had begun to make inroads into several significant fuel markets traditionally served by coal. Indeed, the growing use of fuel oil in the first decades of the twentieth century was an important transitional phase in the decline of "King Coal" and the rise of its successor.