Understanding this transition requires a look at the two-sided connection between energy and human well-being. Energy contributes positively to well-being by providing such consumer services as heating and lighting as well as serving as a necessary input to economic production. But the costs of energy--including not only the money and other resources devoted to obtaining and exploiting it, but also environmental and sociopolitical impacts—detract from well-being. For most of human history, the dominant concerns about energy have centered on the benefit side of the energy-well-being equation. Inadequacy of energy resources or more often of the technologies and organizations for harvesting, converting, and distributing those resources has meant insufficient energy benefits and hence inconvenience, deprivation and constraints on growth. The 1970’s, then, represented a turning point. After decades of constancy or decline in monetary costs--and of relegation of environmental and sociopolitical costs to secondary status--energy was seen to be getting costlier in all respects. It began to be probable that excessive energy costs could pose threats on insufficient supply. It also became possible to think that expanding some forms of energy supply could create costs exceeding the benefits.