Systems Analysis and Simulation in Ecology, Volume III, and its companion, Volume IV, grew out of a symposium, Modeling and Analysis of Ecosystems, held at the University of Georgia, 1-3 March 1973. The purposes of the meeting were to (i) review the status of ecosystem modeling, simulation, and analysis; (ii) provide a forum for interaction between U.S. International Biological Program (IBP) Biome modeling programs and selected non-IBP investigations involving systems approaches to ecosystem analysis; and (iii) identify and promote dialogue on key issues in macrosystem modeling. The volume is.