The denizen of the late twentieth century who fills his automobile with gasoline, covers himself with suntan lotion to block out the ultraviolet, turns on his VCR by means of a remote control device and worries about the nuclear power plant just down the river probably feels himself to be quite at home with the concept of energy. Depending upon his education, he may or may not be aware that there are some cryptic mathematical equations behind it all, but on the whole he is content to turn the switches on and off and let someone else worry about the details. I daresay the reader, even if he or she is an economist, more or less falls into this category.