The Milnes never define a ""perfect world,"" but one suspects that they use the term to mean a fuzzy environmentalists' dream of a ""natural"" world incompatible with civilization as they know and accept it. You don't get much clue to their thesis from the vacuous, disjointed introduction, which ranges from an argument-by-example against enforcing environmental regulation to ridiculous examples of modern progress (computers, Frisbees, jets) to such muddled statements as ""Civilization accumulates over thousands of years, yet the culture remains precarious. It could be lost in a single generation if no one accepted it."" After that, they show that the dream of ""living off the country"" as the Indians did is impossible for us (and that, it's implied, takes care of the simple-living movement); then they survey different ecosystems (forests, deserts, mountains) with a word on what each would be like in a ""perfect world,"" and some suggestions to the young for more feasible conservationist activities--on the order of home gardens, identifying birds in your neighborhood, and keeping ""a record of hollow trees that merit protection."" This emphasis on kiddie busywork would be fine if it were not implicitly offered as an alternative to more concerted battles and political approaches. Their chapter on rivers begins with the observation that ""all over the world, fresh water is increasingly unsafe to drink,"" but goes on to point up a conflict between the needs of beavers and those of trout. The chapter on ""The Wild Shores"" concludes that seaweed is valuable; that ""no one would spill oil"" on a perfect earth but careful oil-handling would raise prices for consumers; and--merely slipped in without the discussion that might make it a relevant point--that oil rigs are not hurting the habitat of sea animals and seaweed. Perhaps their aim is to show that there are conflicting claims on all our resources, and choosing is not that easy; but this is not news, and the Milnes make no effort to sort out these claims and the interests behind them or to assess their environmental impact in any but a random, perfunctory, and covertly querulous way.