Colin R. Townsend is the Director of the Ecology, Conservation and Biodiversity Research Group at the University of Otago. He has published over 150 ecology papers and books, including the best-selling and award-winning Ecology, 4th Edition, with co-authors Michael Begon and John L. Harper. He is also co-editor of the international journal Freshwater Biology. Michael Begon is Professor of Ecology in the School of Biological Sciences at the University of Liverpool. He has authored several books in addition to Ecology and around 150 research articles. His current research interests are focused on the population ecology of pathogens in wildlife populations. Robert Howarth chairs the International SCOPE Biofuels Project, directs the Agriculture, Energy & the Environment Program (AEEP, formerly AEP) at Cornell University, and represents the State of New York on the science and technical advisory committee of the Chesapeake Bay Program. He is the Founding Editor of the journal "Biogeochemistry" (Editor-in-Chief from 1983 to 2004). He has worked extensively on environmental issues related to human-induced changes in the sulphur, nitrogen, phosphorus, and carbon cycles, the impacts of global climate change, and interaction of energy systems and the environment.