No mammoth goes unmourned, no butterfly vanishes without a trace, in this searching survey of the demise of creatures great and small. Beginning with a summary of basic information on evolution and ecosystems, which emphasizes the interconnectedness of organisms and habitats, the Ehrlichs document the recent sweeping devastations wrought by both over- and underdeveloped countries in an overpopulated world. Extinctions have come by deliberate acts (bounties on bison, wholesale slaughter of passenger pigeons); by overkill through nonselective pesticides; by urbanization and industralization and other acts that inadvertently and indiscriminately lay waste forests, destroy habitats, lead to soil erosion, desertification, floods or droughts. Life is also increasingly endangered by ""ORV's""--off-the-road vehicles that churn up parks and countryside. Frequently butterfly species--a specialty of the Ehrlichs--serve as harbingers of change, their demise multiplying through the chain of life in a particular habitat. Where will it end? Here the Ehrlichs find some glimmers of hope: conservationist forces have won a few battles; there is a growing realization that large natural reserves must be maintained, and good land management practiced. (A few countries--Costa Rica, Brazil--and a few corporations are even complimented for major preservation programs.) On the critical problem of world population, the Ehrlichs are optimistic; but it will also be necessary, they recognize, to educate the immediate-profit mentality toward long-range stewardship of the land, and there seem few signs of that. In balance, then, a well-told and sobering tale of planetary plundering that may inspire the defenders of snail darters, but leave the dam-builders undaunted.