The authors of the book The Limits to Growth theorized that, among other problems, running out of basic resources such as petroleum would cause a collapse of industrial and agricultural production as well as a resulting loss of a large part of the world's human population. Although crude oil still appears to be relatively abundant and supplies most of the world's material from which gasoline is refined, other fossil sources of gasoline seem to offer commercially viable alternatives. The earth is hardly exhausting the resources to make abundant, affordable gasoline. However, the enjoyment of plentiful gasoline may not be in the future in spite of its feasibility. Political interference with the construction and operation of refineries and synthesizing plants places the world at the mercy of those who believe they must deprive humankind of cheap fossil fuels. Their persistent obstruction of the construction and Their persistent obstruction of the construction and expansion of petroleum refineries has already proved capable of contriving a mild energy crisis.