From dippy title, Doty and Maar jump to flippy preface: One reason the earliest humans survived was that ""People discovered energy, which can simply be defined as the capacity to do work""--yes, but how does that definition clarify what goes before? And very little is clarified in their carelessly worded, fitful survey of 20 or so energy sources, from fire (""Fire made heat and heat changed things. It made some wood harder""--but what wood? how? and so what?), water (""the first natural force people harnessed as an extension of their own muscles""--again, no elaboration on this adult cliche), and animals (""Man power and animal power are really poor ways of getting things done""--what things?) to the atom. (Scientists ""learned that the atom could be split and heat resulted. This splitting of atoms can be controlled so that the heat energy boils water to make steam""--so much for the actual splitting of the atom.) The authors end with the usual band-aid suggestions for energy conservation. (""Urge your family to stay under the speed limit . . . and lower the thermostat to 68""--who can afford 68?) Well, they didn't waste any brain power on this.