Walker's plea for the ethical stewardship of wildlife is backed up by some 27 succinct case studies on the ecological roles of predators, spiders, bats, and other often maligned animals. The defense of predators is most pointed: for example, Walker cites recent feeding research in characterizing the mountain lion as ""one of nature's most precise game-management tools"" and criticizes hunters, who view the lion as a competitor for deer, for their contradictory and self-serving arguments. Similarly, young readers are urged to rethink their attitudes toward ""pests."" (""Spiders should be protected. Ignore their ugliness and learn to appreciate their interesting habits."") Alas, these closely argued briefs don't encourage the sort of familiarity that would change any child's ingrained attitudes, nor will they arm him to rebut advocates of coyote kills or help him convince his parents to give up their chemical weed killers. But if the individual arguments have been stated more effectively elsewhere, Walker's compressed survey makes them accessible to grade-school investigators with limited attention spans. Serviceable.