Y OU'RE not one of those developers, are you? Carl Sauer asked me in 1972. My answer was a somewhat uncomprehending but truthful no. The ensuing discussion ranged over Missouri extension agents who wooed farmers away from crop rotation with ammonium nitrate, side effects of the Green Revolution, dooryard gardens in the tropics, and in general. I have only begun to gain a philosophical and theoretical basis for understanding the significance of Mr. Sauer's question. Ivan Illich triggered my awareness of the convergence of the social and environmental problems generated by conventional approaches to in the Third World.' Nicholas Georgescu-Roegen has contributed most to my understanding of why the application of conventional economic theory has exacerbated these same problems.2 Accepting the irresistibility of the pressure for on one hand and the lack of survival value of the North American model so eagerly proffered and desired on the other, I looked for a coherent framework for evaluating and presenting more viable alternatives. Howard T. Odum provides such a conceptual model, which appeals to the geographer because of its spatial and temporal dimensions and which also brings to bear powerful physical and ecological principles for problem analysis.3 The Second Law of Thermodynamics, or Entropy Law, is the underlying principle, and it can readily be applied to evaluation of alternatives. Work, associated with the and maintenance of structure in any system, involves the dispersion of a comparable amount of energy as waste, or entropy. In a much broader sense, the entropy generated can conceptually include such side effects as pollution, erosion, and loss of cultural values. Odum uses energy as the common denominator for evaluating complex system processes. Net energy calculations allow the true cost of a project to be evaluated and compared with alternatives. If the sum of the energies expended and those lost as a result of entropic side effects exceeds the benefit gained from a project, then no development has occurred. The net energy yield is negative. Much of what passes for is positive only in isolation and in a limited temporal and spatial framework. Costly hydroelectric projects that inundate agricultural valleys and reduce the productivity of downstream levees and fisheries are obvious examples of projects suitable for net energy analysis. My philosophical goal in consulting is to partially bridge the gap between the type of lowtechnology qualitative I believe to be viable and the process actually under way. The first opportunity came through a short-term contract financed by the Organization of American States (OAS) with the National Office of Natural Resource Evaluation (ONERN) in Peru. Parenthetically, both ONERN and the granting department in OAS were organized by an applied geographer, Wolfram U. Drewes (now with the World Bank). ONERN is highly respected for its work in natural resource inventory and evaluation. It provides basic data on soils, geology, hydrology, and forest resources throughout Peru, with particular emphasis on the expansion of irrigation in the coastal valleys. In 1974, ONERN became explicitly and officially involved with the environment. My role has been to help define a functional strategy to fulfill the extremely broad and nebulous mandate given by the enabling legislation. A major conceptual difficulty that had to be faced in ONERN was the close identification of