Eckholm, who collaborated with Lester Brown on By Bread Alone (1974), reminds us of the geographical realities underlying the Malthusian dilemmas of the Club of Rome Limits to Growth (rev. ed. 1974). Focusing on the ""marginal"" ecologies of arid and semi-arid zones, mountain regions, and tropical rain forests, he traces an insanely recurring pattern of quite literally ""lost"" ground--catastrophic topsoil and water depletion. In dozens of the world's chanciest ecologies, deforestation through firewood gathering hastens the process of arable-land erosion following over-cultivation (traditional fallowing practices are disappearing everywhere). The precious topsoil ends up as spectacular silt deposits in rivers, newly dammed reservoirs, and irrigation systems in the Himalayas, West Africa, the Philippines, and Indonesia. Elsewhere, careless irrigation is estimated to have undermined ""the productivity of at least one-third of all the world's irrigated land"" by rapid salinization. Eckholm plainly tells us that the Green Revolution technology of improved cereal strains and fertilizers cannot prevail against nearly universal elementary misunderstanding of how the earth's fragile, complex topsoil resources are related to patterns of land use. His clear, restrained study (co-sponsored by the UN Environment Program and the Washington-based Worldwatch Institute) offers no solutions and little scope for optimism. What it does offer is systematic and minutely documented access to a range of very important facts.