This is the first special issue in the 12-year history of "National Wildlife," and is devoted entirely to endangered species of animals and plants in the United States. An overview of the problem stresses the impact of man's haphazard development, suburban sprawl, and urban pollution upon a fragile environment, resulting in dozens of wild animals throughout the country being in imminent danger of extinction. Immediate action is advocated to control growth, conserve resources, and preserve the wilderness. A section dealing with the past illustrates that species are constantly emerging and disappearing, but the evolution of man has greatly hastened the extinction of many forms of wildlife. Lists are provided of extinct, endangered, and threatened species of animals. Until the 17th century, the 62 animals listed as "extinct" flourished in the United States, and most of them disappeared in the 20th century. There are 109 mammals, birds, fishes, reptiles, and amphibians classified as "endangered" species (presently threatened with extinction), and 69 species which are now decreasing at an alarming rate are listed as "threatened." Some answers are suggested to reverse the trend toward the elimination of the nation's wildlife. This publication is extensively illustrated with excellent colored photographs of representative organisms. (JR)