The author, an ecologist, notes the prevailing global trend toward uniformity and makes a counter-plea for diversity. The human habitat as well as that of other animals is at stake. Mr. Dasmann points out the dangers of monoculture, the values of biological diversity as related to stability and adaptability. He discusses specifically the concepts and actualities of wilderness in the United States from the Everglades to the Redwoods, indicating the conflicts of private and public interest and, even within conservation-minded groups, the differing emphases, research playing second fiddle to preservation and recreation. Since it is the city dwellers who resort to the wilderness, they must be responsible for it; but a city in wyoming would take care of wilderness in Wyoming better than a distant megalopolis, and Mr. Dasmann plumps for federal creation of new cities to absorb the population more effectively. His concern extends from high density, high variety cities and their human inhabitants to the far reaches of the Arctic or the tropics. He would set up a World Heritage Trust to preserve such places as Serengeti, Aldabra (a turtle-inhabited island now threatened by British air base plans); planning ""against progress"" is essential. He sounds an alarm and presents a range of information and ideas to stimulate, activate.