Professor Charlie Hall is a systems ecologist with strong interests in energy flows in natural systems and human society. He received his Ph D from Dr. Howard Odum at the University of North Carolina at Chapel Hill in 1970. His work has involved streams, estuaries and tropical forests, but has focused increasingly on human-dominated ecosystems in the US and Latin America. He is best known for developing the concept of EROI, or energy return on investment, as it relates to e.g. migrating fish and obtaining oil and gas. Hall’s latest focus has been on developing an alternative approach to economics called biophysical economics, an attempt to understand human economies from a biophysical rather than just social perspective. He recently co-authored “Energy and the Wealth of Nations: Understanding the Biophysical Economy” with economist Kent Klitgaard. Carlos A. Ramírez-Pascualli is a Ph.D. student in environmental science at the State University of New York, College of Environmental Science and Forestry (SUNY-ESF), where he is doing research on the biophysical aspects of economic systems, specifically on the relation of oil production to the Mexican economy. He holds degrees from some of the leading institutions in Mexico and Latin America: M.Sc. Economics from El Colegio de México (COLMEX), and B. Sc. Industrial Engineering from Universidad Nacional Autónoma de México (UNAM). Before entering the Ph.D. program at SUNY-ESF, he was part of the team that developed the main information system at the Federal Competition Commission in Mexico. Previously, he worked as researcher and teaching assistant in several microeconomic courses at COLMEX. In addition to his official degrees, he has studied statistics and enjoys reading as much philosophy as he can.